Marco knows his soulmate is younger than him. He knows this because a mark never shows up until he's twenty-seven.

Twenty-Seven.

A soulmate's thoughts are written somewhere on your body, almost always somewhere easy to see and most commonly on a hand or arm. For instance: Haruta has a wavy script on her inner left forearm but Rakuro has his on the top of his right knee.

Covering your soulmark is cultural. Izo keeps his covered at all times. He says it's private and that's not uncommon. Thatch grew up with the tradition of only showing your soulmark after you find your soulmate (and covering the mark up again is sign of either deep disgrace or that your soulmate has died). He keeps his uncovered despite never meeting his soulmate because he 'hates stuffy traditions'. Whiskey insists on constantly wearing short skirts because her soulmark is on her right thigh and she's proud to have one.

Not everyone has a soulmark.

Oyaji says that he used to have one on his right wrist, many years ago. Vista, Jiro, and Curiel have never had one at all. Fishmen, such as Namur, don't have any. It's a distinctly human phenomenon which has led to interesting meetings when their soulmate isn't human. One of his division members had been the soulmate of a mermaid. They were teenagers and it had taken months before they finally realized that her thoughts were reflected on his skin.

Marco had never been bothered by not having a soulmark. He was free on the open seas and loved sailing under Oyaji with his rough and tumble family. He doesn't need a lifelong friend worrying about him and it would be distracting to follow another person's life story all the time.

One day though, it happens. A dark smudge is there, plain as day across the back of his left hand and he can't wash it off. He corners Thatch thinking it some kind of prank but the chef fervently denies it until suddenly he stops mid-sentence. A thought seems to have struck Thatch like lightening because suddenly Marco's hand is caught in a vice grip and Thatch is staring in awe. A shiver races up Marco's spine before Thatch is suddenly grinning and yells out, "Oh my god! Marco has a soulmate!"

And that's how everyone found out (including Marco) that he had a soulmate after all.

Most soulmates are platonic.

It's like a guaranteed best friend who will always understand you no matter what. Some pairs meet and fall in love and have kids (who are considered to be blessed with good fortune) but most soulmates never meet at all. The world is huge and not everyone sails so a lot of people find soulmarks pointless. Haruta, despite having her sleeves rolled up now and then to view her mark isn't vested in meeting her soulmate. If it happens it happens but her life is here on the Moby Dick and her soulmate has been thinking about baby names so they clearly have a lovely life of their own. She likes the idea of being a mysterious Aunt.

Now, age differences are not unheard of. Usually though it's between a parent and a child or a child someone is meant to adopt. Rakuro's is like that. He'd been apprenticed to a fisherman when he was twelve who practically became his uncle. He checks his mark daily to make sure the old man is still alive.

Soulmates with an age difference almost always meet. Some people even consider it necessary for the younger to survive. Marco does not want that kind of responsibility. He's a pirate – not a babysitter. He comforts himself with the thought that he'll save a stray life somewhere and then they'll pass each other like boats in the night. It doesn't have to mean anything.

(His brothers and sisters insist they can't wait to meet the adorable child he's meant to adopt.)

It takes almost two years before the smudge turns into a discernible thought and it is, predictably, Food.

Now, calling soulmarks a person's 'thoughts' is a bit misleading. It's more like their goals or their driving motivation or just something prominent on the front of their mind. Just last week Whiskey's mark had spent days as I hate being sick before eventually clearing up to FREEDOM.

For a toddler, their first clearly written desire being 'Food' is completely normal and expected.

Thatch insists they throw a party because his soulmate is growing up. Why the entire ship loves to gossip about this is beyond Marco.

It isn't for a few weeks that Marco notices something missing. Never once has he seen this kid ask for his parents. A lot of the time the mark remains a smudge with brief shows of Food, Cold, Sleepy, Hurts, and Angry. These are all normal for a kid but so is requesting comfort. Eventually, the word Gramps shows up and Marco relaxes. It's not like he watches the mark closely so he could have easily missed it but it's comforting to know that this kid is with some kind of family.

He won't talk about it, but he worries about this kid. He feels responsible despite never meeting him. Maybe it will be like Rakuro's 'Uncle' and this is just someone he'll take under his wing. Maybe it's more serious than that and one day he'll save this kid's life. There's so many ways this could happen but one thing he knows he's not cut out for is raising a child. He's glad that 'Gramps' is around to take care of him.

The kid is three and Marco is thirty when the words SAVE ME stop him cold in the middle of a report. His heart stops for a breathless instant and he has everyone's attention in moments. A cloud settles over the room as they all wish they could do something. This kid, while being Marco's, is all of theirs. They've followed him closely and three is too soon. They don't know where to go or how to help and what's going on and it leaves them all feeling helpless.

It's Oyaji who puts a gentle hands on his son's shoulder and comforts him. "I know you two are meant to meet. He will get through this."

And he does. Just five minutes later the writing changes to Shitty Gramps which is both soothing and not as it leaves Marco with two unanswered questions. The first is 'Was the kid actually safe with 'Gramps' ' and the second is 'Where did a three-year-old learn to curse?' On the scale of curse words 'shitty' isn't that bad but it raises a lot of questions about what kind of environment his soulmate is growing up in.

Nothing else alarming happens after that but it's forevermore 'Shitty Gramps'. Marco has a gnawing urge to figure out just what this guy did but represses it. It may be just a nickname but it may also be a sign of lost trust.

It happens one day while Marco's doing paperwork that a truly distressing phrase appears on his hand. Demon Spawn. He watches it for days as it shifts through several similar sentiments. Son of the Devil, Devil Child, Filthy Brat.

I should have never been born

On the night this appears Marco flies for hours. He wishes he could get drunk but his regenerative powers prevent that and he doesn't want to just sit there and cry. How could someone put such ideas in a child's head? How could they say that?

His soulmate, a four-year-old child, just thought he should never have been born. This kid will never be the same. Their innocence has been lost in just days (or was it lost in that desperate 'SAVE ME' just last year?) and Marco wants to tear whoever it is apart.

When he finally exhausts himself he stumbles onto the deck where Thatch meets him with a mug of beer and a plate of food. The words are still stark against his skin and he's thankful when Thatch says nothing, merely matching Marco's thoughts with the murderous glint in his eyes.

Demon Spawn becomes the most common phrase on his hand and for the first time, Marco considers covering it. He hates seeing it, hates knowing the world has already beaten down a child into thinking he shouldn't exist. Marco knows more than most the darkness that lies in the world but at least he'd had a childhood. He'd had his parents and a stable life until he was fourteen. This kid didn't even make it to five.

The only good thing Marco can find in all of this is that he finally knows his soulmate is a boy. 'Son of the Devil'. But who's the Devil?

Eventually, the day he'd been both dreading and looking forward to came. A Soulmate lies brazen across the back of his hand and he's curious just what this kid is thinking. Is he excited? Scared? Does he want Marco to show up or does he not care? And what is his soulmark showing right now?

I don't care shines up at him and Marco sighs. It's not that surprising but one day, he'd like to show this kid that there are better people in the world than those who had put him down.

When they first run into Shanks, Marco doesn't think anything of it. It happens from time to time. They meet up with the Red Force, Shanks is annoying, they exchange gossip, and then they part. The 'SAVE ME' scare was still a hot topic the last time the crews had met up so he's not surprised when it's brought up. What does surprise him is why.

"It's on my ankle so I always thought it was just a smudge of dirt but now it's words! Look!" Shanks yanks his right foot up with both hands and shows the word FOOD stamped across the inside of his ankle. "I have a kid! Marco, we both have kids!"

Marco pushes the annoying captain over (who disappointingly manages to get his foot back under him to stop his fall). In the end though, Shanks asks for advice of all things. Like Marco knows anything. It's like an incomplete book. He gets a note here and there but there's no good way to know about the kid's life and unless they meet, he'll never know.

Shanks corrects him. It's not 'unless they meet', it's 'until they meet'.

The next year comes with good news. There's a solid week of What's up with that kid before A Friend and He doesn't care take turns for about a day. It finally settles into I have a friend and Marco smiles. It's nice to know that the kid has a friend. That the adults who'd told him he was the Devil's Spawn aren't the only people around him.

It gets even better when the next phrase to come up is We're going to be pirates. Thatch insists they throw a party.

Marco is both relieved and worried. It makes a lot of sense if this kid becomes a pirate and Marco takes him under his wing but at the same time, being a pirate is dangerous. He puts it out of his mind and takes solace in the kid finally having something good happen.

Things fall into a pattern after that. There's the basics of I'm hungry and Shitty Bandits (a term that had been coming up almost as long as 'Shitty Gramps') but a lot of the time was I have to get stronger, We need more treasure, and Fuck the world. Marco likes to imagine this is with a Devil May Care attitude but he has a suspicion that a lot of it is driven by hatred.

At least he's not alone.

Marco doesn't think about his soulmate much for the next four years. The boy has settled into some kind of pattern with caretakers and a best friend. Even though he's bitter at the world, there haven't been anymore heart stopping moments. The only alarming thing that had happened was a SHITTY GRAMPS ALERT which Marco wrote off as the kid being caught for bad behavior.

Shanks comes back from a year long hiatus missing an arm and with a huge smile. There's a lot of talk; rumors that his strength has failed, that he's all washed up. There's talk of him having lost his chance to be the next king. What there isn't, at least not openly, is condescension. Shanks lost his arm saving the son of his soul and no one was going to tell him he was wrong for it.

They're partying on a sandy beach while exchanging information. The Whitebeards tell the Red Force about what's changed in the last year and the Red Force talk about their captain's beloved son and barmaid.

Shanks is sitting by one of the bonfires, rum in his only hand. Marco takes a seat across from him and refuses to shift nervously. He wants to ask a lot of things. What was it like? Did you know right away who he was? Did you accept each other easily? Were you ok leaving him? Is he ok with you being gone? Why didn't you bring him with you.

Was it worth it?

In the end he doesn't say anything and Shanks' smile says everything he needs. It was wonderful. It doesn't matter how they met or if they clicked right away. He was sad to leave but he knows his son will be ok.

And he'd do it all over, even losing his arm, for the sake of his soul son.

This time, it's Shanks who gives out advice. "You don't have to worry so much. Kids are strong, resilient. They can bounce back from anything." There's a twitch in his smile as he resists laughing at some kind of inside joke. "From experience: You really can't tell what a kid is like just by viewing their goals and desires. My kid is a little ball of sunshine even though his thoughts are almost always centered around his stomach."

It soothes Marco, just a little, to hear that even though his soulmate is driven by hate (as far as he can tell) that doesn't mean he acts angry all the time.

Then Shanks ruins the moment. "I just had a brilliant idea! If our kids meet and become best friends then we can co-parent together! Then you'd have to join my crew!"

Marco glares before walking off in a huff. Shanks is an immature asshole but just this once, he'd given some helpful advice.

It's only five days later that something new pops up in his soulmate's thoughts.

Why won't that kid just die already

Needless to say Marco is worried. His soulmate is ten. Ten. He should not be thinking about death. And there's a lot of ways he could take that sentence. Is he concerned about this kid? Is he just standing by or is he thinking of doing something? Is he (and Marco doesn't even want to think it) trying to kill the boy and upset that he hasn't succeeded? Marco knows the dark corners of the world and has seen the worst humanity has to offer. Demon Spawn and I should never have been born are still common along with the more… optimistic I'll make everyone acknowledge me. All together it paints a bit of a bleak childhood and he assumes more than anything that this kid is raging at the world.

Marco's a pessimist. Still, he tries to brush away the (somewhat likely) thought that his soulmate is trying to commit murder.

It's at the crack of dawn close to two months later that something changes. He's climbing up the rigging to check with the nightwatch when he catches sight of I NEED TO SAVE THE KID. Marco still doen't know what's going on, but he feels a swell of relief that his soulmate has decided to save this kid instead of continuing to wish he was dead. By breakfast, his soulmark reads This kid is an idiot and stays that way for the rest of the day.

A lot of new thoughts cross Marco's hand after that.

This is so much fun

That idiot

HOW THE HELL DID LUFFY GET EATEN BY A CROCODILE

Protect Luffy

I didn't know life could be so fun

Pirates

BROTHERS

It's that word that has Marco beaming. The entire crew start giving him wary looks and avoiding him. Honestly, it's a bit annoying (he can smile and be happy sometimes; it's not the end of the world.) It's Thatch who finally gets up the courage to ask him.

Marco knows this will only bring another impromptu party over the unofficial child of the Whitebeards and for once, Marco wants it. "You know that kid he decided to take under his wing? Well the two of them swore brotherhood, yoi." He's beaming with pride. He knows it. But there's something so Whitebeard about swearing brotherhood instead of just friendship that cements that this kid belongs on their crew.

Thatch runs off whooping and hollering. Marco doesn't even roll his eyes because he feels the same. After all the fretting (and mother hen jokes) things are finally looking up. Marco can finally see why this is his soulmate.

The next glorious thing to show up on his hand comes with a bitter afterburn.

HOME

For the first time, this kid has a home. Somewhere he feels loved and accepted. Marco is so happy for him but it's bittersweet. No one should be discovering the feeling of 'HOME' when they're ten.

This 'Luffy' kid has been good for him. He can't possibly know, just as his soulmate almost definitely doesn't know, that he's an honorary Whitebeard. (There's a chance his soulmate knows. Marco has no idea what thoughts of his the kid even sees.)

When change comes again, it's devastating.

Marco has always paid attention to capital letters. His soulmate's writing isn't quite messy but it's not very neat either. The shapes are square but there's the slightest tilt like someone tried to teach him calligraphy and failed. His capitals though – the raging thoughts that scream through a person so powerfully it's all someone is in that moment – are always something Marco has watched for since the very first 'SAVE ME' all those years ago.

He barely catches a glimpse of DON'T LEAVE before it morphs into HE LEFT.

Luffy. It has to be Luffy. No one else mattered to his soulmate the way Luffy, his sworn brother, mattered. If Marco knew where to go, he'd storm in there immediately and save the kid. He doesn't even know this boy, but he'd saved Marco's soulmate and losing Luffy might destroy him.

For the next week all of the Moby Dick is down as He left remains a blight on Marco's hand. Not a single one of them believe Luffy left of his own accord but that doesn't stop it from hurting.

It's a terrifying day when things finally change again.

PROTECT LUFFY blazes across his hand. As relieving as it is to know the boys are back together, the vehemence of needing to protect the other boy is worrying.

When it changes to FIRE just a few minutes later Izo takes Marco to his cabin so they can wait out the drama in private. This kid… his soulmate…

He hasn't even met him. It's too soon. He has to get out of this.

It goes back to PROTECT LUFFY and that's better. Familiar.

PROTECT LUFFY

GET TO SAFETY

SABO

The last one confuses them. They haven't seen anything about a Sabo before. Did they cause the fire?

BLUEJAM

Another new name. Maybe this was the fire starter? Maybe it was both?

Or maybe it was people his soulmate cared for who were also in danger.

For once, Marco wishes his hand would show him every single thought running through his soulmate's head because knowing so little is more terrifying than anything Marco has experienced as a pirate.

LUFFY

I WILL NOT RUN

WHAT ARE YOU DOING HERE

FIND SAFETY

It's an agonizing hour that lacks the necessary context before the first non-capitals show up on his hand.

They're not comforting.

I killed Bluejam

Marco really hopes that's the guy who started the fire.

The next week is a mantra.

Get home
Find Sabo

It's a set of goals. Two tasks vitally important to him that are too separate to be one but not completely unrelated.

If Sabo is someone he cares about, they hope he's alright. If Sabo was responsible for the fire, he might be searching for revenge.

Haruta is quick to point out when it starts morphing.

Luffy is safe

Everyone breathes a sigh of relief before it changes again.

SABO

There's nothing else. No explanation, no attached emotion, but for the next two months that's the only word stamped on Marco's skin.

When it finally slips back into a familiar pattern of Luffy, I need to get stronger, Shitty bandits, and Pirates everyone is relieved. Whatever had happened, life was moving on.

One day, when they finally have their unofficial kid, the Whitebeards will get the whole story out of him. Who are Bluejam and Sabo and why was there a fire? How did you get out safe? Were either you or Luffy hurt?

Nothing happens for eight months – almost an entire year. But when it does, it's terrible.

LUFFY DON'T DIE

They don't know what happened. They have no way of knowing. But none the less some of the crew set up a vigil and offer their own prayers. That kid, Luffy, is clearly the most important thing in the world to their littlest brother and losing him would be devastating.

After two days the words turn into I'm sorry and I'll protect you for the next two months.

Once again, things return to normal and this time they stay that way for the next six years.

Finally the day comes. A day they've all been looking forward to.

Today's the day I become a pirate

Another party is thrown because their newest brother is finally on his way to them. Marco is bothered for updates daily and for once, his soulmark is informative.

My first crewmember and First Mate

Damn Marines

My own ship

HOLY SHIT I'M FIRE

There's a lot of laughter at that one. Clearly he's just eaten a logia devil fruit, an extremely powerful one at that. This will also make him much easier to find.

The Grand Line

The crew is practically vibrating in anticipation. It's only taken him one month to leave whatever blue he's coming from. It means he's strong. It means he's ready. It means he'll be there soon.

Marco wishes the crew would just settle down. Really, it's not that big of a deal. Yes, Marco is curious and does want to meet his soulmate but, it's not some grand adoption like Shanks. The Yonko had been thrilled at the thought of being a father, of having a family to look after. It reminded Marco just a bit of Oyaji – a distasteful thought he quickly pushed away. It was never like that for Marco.

He worried. The kid was twenty-seven years younger than him. Seventeen to Marco's forty-four. And Marco, while admittedly a 'caretaker' for the motley crew, didn't see himself as some kind of father. A mentor, maybe. He could do that. A friend, even. He's always felt that the kid could use more friends.

At the very least he didn't look forty-four. Thanks to his devil fruit he was aging extremely slowly and looked to be in his late twenties. It would just seem awkward to take a paternal role in this kid's life.

Besides, he was sure it wouldn't be appreciated.

Honestly, he wouldn't have even paid that much attention to his soulmate (outside of notable distressing moments) if the whole crew hadn't insisted on knowing what was going on. It was unusual to take an interest in someone else's soulmate – it was a private affair after all – but there was something about Marco being paired with a kid that had everyone wanting to know everything.

It was exasperating.

Still, he was curious and he wanted to meet.

Three months into his career as a pirate, it happens.

MY FIRST BOUNTY

'Fire Fist' Ace

His new epitaph is worn like a badge of honor. His bounty starts at forty-four million and Thatch makes a joke about how it must be fate. Marco promptly kicks him off of the deck.

His bounty poster is hung with the rest of theirs showing a handsome teen with an orange cowboy hat tilted over his eyes, freckles across his nose and cheeks, and a smirk that's both prideful and charming. Haruta points out that he's a real lady-killer. Marco ignores her.

Finally, a name and a face.

They keep tabs on him through their information network which Marco is grateful for. For one, they have a clearer idea of what's going on and two, it means they don't bother Marco all the time for updates.

The only real peculiarity that comes up is when Marines turns into SHITTY GRAMPS ALERT. Was his grandfather a marine? It would kinda make sense. 'Shitty Gramps' didn't come up all the time so if it was only when he'd visit…

Marco would ask him when the time came.

Other details about him trickle in. He's a D, which, to anyone who's known a D, can only mean trouble and a voracious appetite. He's good with children; this is reported on several islands and the Whitebeards put it down to him being a big brother. He's polite, in his own way. According to a rumor from Hibiscus he been thrown through the wall during a bar fight and bowed in apology before leaving some treasure for all the trouble. It was… odd. A lot of the crew snickered at the story but for Marco, it came with relief.

At first, the kid had seemed so angry. 'Fuck the world' had been a far too common phrase on his hand. Then Luffy arrived and it never showed up again. He knew, if he ever got the chance to meet Luffy, he'd thank the boy properly. He may not have even realized the darkness that surrounded his brother until they met. Marco wouldn't know. He has no idea who Luffy even is.

The most intriguing detail they learn though is his tattoo. ASCE with the S crossed out. They have no doubt that the S is for Sabo, whoever that was. Or is. The mystery deepens and rumors are rampant. Is Sabo someone he lost? Was it someone he extracted revenge from? Was the S a warning? A memorial? Marco found the latter most likely.

Whoever Sabo had been, he was someone Ace had lost.

Ace blazes through Paradise and bounties alike until he makes it to Saobody in seven months. Just in time for New Years. He'll be entering the New World soon and the Whitebeards cheer not only for the incoming year but for their upcoming brother.

It's April, eleven months since Ace set out to sea, and they've gotten word that he's fighting Jinbei not too far from them. It's a no brainer to pick him up.

The two-hundred-million beli rookie and the Shichibukai are lying in the sand exhausted after a five day fight that they've finally called a draw. The Whitebeards are already impressed and the fact that Jinbei is only fighting him because he's been mouthing off about taking Oyaji's head is promptly ignored. The kid is just trying to prove himself like so many others. They're not worried.

So of course Whitebeard has to fan the literal flames. "Which one of you said he'd take my head? If you want it so badly, here's your chance."

Marco gives his father a deadpan stare. Really? This is how he's going to invite Marco's soulmate on board? What happened to having already adopted him?

The Spades immediately surge forward to protect their captain (a good sign to have such a loyal crew) before Ace summons up the last dregs of his energy to form a wall of fire. He tells his crew to escape saying that he'll take Whitebeard by himself so they can get away. Marco feels pride, like a warm fire in his chest.

Ace charges Whitebeard and gets smacked to the ground. Marco's ready to carry the kid to the infirmary when he starts standing back up. It's more than impressive. The kid has been fighting for the last five days, created a giant wall of fire, and just taken a hit that was meant to knock him out from the strongest man in the world.

And this is when Oyaji finally asks Ace to be his son. To join their crew. Their family.

"DON'T SCREW WITH ME!" He shouts as he launches himself again. The kid stays down this time and Marco checks his hand.

No fucking way

Marco doesn't know if it's in disbelief or anger but, from the resounding rage in his soulmate's voice, he does know this has been an utter disaster of a first impression.

Marco is the one who carries him to the infirmary and once again, he finds himself worried. This kid had pushed himself to the brink of exhaustion and kept going. Between that and his injuries (nothing life threatening, thankfully) he wouldn't be waking up for a least a couple days. The kid takes too much on himself, but that's ok. He'll have a huge family to back him up from now on.

It's only a couple hours later that Marco gets a good look at his soulmate. Ace has been cleaned up of most of the blood with a few stitches and bandages here and there. The most striking reveal is a face full of freckles. He'd seen the bounty posters – he's known what his soulmate looks like for almost a year – but there's something so innocent about the freckles spattered across the bridge of his nose that Marco can only describe as cute.

He's watched this kid grow up, sort-of; like an uninvited audience hiding in the wings. Marco can't view the kid as innocent. He's a pirate through and through, and had even killed someone when he was ten. But still, Ace is young. Only eighteen with a trace of babyfat on his cheeks and a map of freckles from days in the sun. He knows he's stared long enough when he starts wondering if the kid has dimples when he smiles.

When Ace finally wakes up he pulls an escape act and the whole crew starts scouring the ship for him. Thatch finds him first, pouting behind some crates on deck, and starts telling him what happened after he passed out. His crewmates are being held on the Moby 2 so they don't cause trouble and they all expect Ace to join the crew.

"You're okay with me… being on your ship without handcuffs or anyone guarding me?" The look in his eyes is suspicious and doubtful. Probably trying to figure out just what kind of trap this is. Well, that's ok. They already knew he was going to be a defensive brat.

Thatch gives him his best smile. "Of course. This is your new home." Eyes sharpening in anger, Ace storms off to find another place to pout. Though Thatch is sure he'd earn a flaming first to the face if he actually voiced that. He does call out one more time though. "By the way, you should go talk to Marco! He's been waiting to meet you for a long time."

Ace looks over in his shoulder in disbelief before storming off with tense shoulders. There's only one case where someone you've never met has been waiting to meet you.

Ace spends the next three days hiding around the ship, stalking Marco. My soulmate makes his motivations obvious. They'll give him time. He's only just learned who his soulmate is while the Whitebeards have been hanging on his every thought for years. Marco feels a familiar twinge of guilt for not protecting the kid's privacy, but not much. He's a pirate. He lives for the adventure of tomorrow and not the shadow of yesterday.

Though he does wonder what Ace's mark shows and where it is. It's not on his hands or his chest with the shirt he refuses to button (and being made of fire there's really no need). It's not on his legs since he's uncovered knee to ankle and that leaves very few places it could actually be. It could be on his ankle like Shanks, only hidden by thick boots. It could be on his shoulders or back – even up on his thigh. The biggest bets are that it's hidden under his elbow brace, just below his tattoo.

On the third night after waking up he comes crashing out of the Captain's room through the wall. He'd tried to assassinate Whitebeard. The Strongest Man in the World. One of the Yonko. The man closest to One Piece. Their father.

Before the outrage has anyone making a stupid move, Whitebeard has already yelled at him for sneaking around and fallen back asleep. Well, if Pops isn't concerned…

It turns almost into a game. Ace attacks Whitebeard and gets swatted like a fly. The whole crew stares cheering and laughing, encouraging the whole spectacle. Their new brother doesn't stand a chance so what's wrong with a bit of roughhousing? Oyaji is clearly pleased.

This crew is insane

Marco at least sees where the kid is coming from but Thatch gives a squawk of indignation when he notices. "Hey kid! Who are you calling crazy?"

Ace frowns at him from the barrel he's perched on frowning in confusion. He looks from Thatch to how he's holding Marco's hand to show off the writing… He jumps down, marches over, grabs Marco's hand and then flushes. The Whitebeard Commanders wait for a comment. Maybe he'll say they are crazy or maybe he'll be mad that they're reading his thoughts. Instead his blush rises all the way to his ears and he marches away haughtily.

None of your business

Thatch snorts.

The rest of the day has it fluctuating between This crew is insane and My soulmate so it's no surprise at all when Ace knocks on his office door that evening.

He doesn't talk at first, just takes a seat on the spare chair and studies Marco. It's slightly annoying but Marco bears with it. He's had a lot of time to think about Ace and has a decent idea of who he is. Ace hasn't. He's been dragged onto a ship where a majority of them have been waiting to meet him since he was born. He's just learned that his soulmate is Marco the Pheonix, one of the most famous pirates in the world. There's a lot of stories about him and there's no telling which ones Ace has heard.

"Is that why you're trying to recruit me?" The question is serious, his voice hard, expression smoothed out – all of it failing to mask the wariness in his eyes.

"In part, yoi. I got teased a lot once we figured out that I had a soulmate and over the years, you've more or less been adopted into the crew. Even before you set sail." Marco offers a wry smile. "When the words 'We're going to be pirates' showed up the whole crew threw a party."

Ace blushes but screws up his face, probably trying to remember when that even was.

"So what? You guys decided some little kid was going to join your crew just because he wanted to be a pirate?" He challenges. His eyes are filled with suspicion and – glancing at his hand – he still thinks the crew is insane.

"No. That didn't happen until you swore brotherhood with Luffy, yoi." He goes white as a sheet and Marco thinks over what he said. Pirates usually don't talk about their families for one reason or another and a big one is safety. No one can hurt you through your family if they don't know you have one. It's why Shanks has never given out his son's name. That and letting his son be his own pirate.

That doesn't solve the problem of having said the wrong thing to his already skittish soulmate so he holds up his hands in a sign of surrender. "You don't have to worry about us." LUFFY is big and bold on his hand, fear lingering in Ace's clenched fists. "We honestly consider him an honorary Whitebeard as well. Look, we were worried about you. A lot of your thoughts before Luffy…" Ace's glare multiplies and Marco is sure he sees a flash of fire in his pupil. He absently wonders if he can do that himself because it's damn intimidating.

He hasn't run off though so Marco continues. "It's not like we just invite everyone's soulmate to join our crew. But you're different. We knew you wanted to be a pirate. We saw your drive to grow stronger. And when you met Luffy and didn't just decide you were friends, but brothers… Well, that's what our crew is to each other. We're not just crewmates or allies, we're brothers and sisters. We knew you'd fit in here and once you became a pirate and we got to see your antics on the seas, the whole crew was excited, yoi."

Ace has calmed down but there's still a wary look in his eyes. "So what do you want from me? Luffy has a soul-father and I don't need a relationship like that."

Marco tucks that information away and squashes the image of Shanks saying co-parents. The odds are astronomically low. So what does he want with Ace? He doesn't want to be his parent and being a mentor doesn't feel quite right either. There has been a thought though, from when he first saw hateful words scrawled in messy block letters. "I want you to know that there's people who care about you. I know you don't need someone babying you or showing you how the world works, but I want to be there for you." Ace is shocked, scrambling with the flood of emotion. Marco knows Ace is unbalanced, that he isn't ready to hear this, but Marco needs to say it anyway. "No child should feel like they shouldn't have been born. Even though it's years late, I want you to know that, yoi."

Wide eyes gape at him before he launches himself out of the room. Marco watches his soulmark morph into a stark NO WAY and understands that it's a panic and not a denial. He'll give the kid time to calm down. After all, Marco has finally said what he's wanted to say (and Ace has needed to hear) after thirteen years.

Ace is moody the next day and sets a new record by attacking Oyaji three times before lunch. Sullenly taking a seat beside Marco, he relents. "So… do you want to hear about Luffy?"

Everyone who hears the quiet comment goes silent which hushes the rest of the room. Ace does a valiant job of staying stone faced and keep his blush light despite the sudden onslaught of attention. Thatch breaks the silence with, "Did he really get eaten by a crocodile?"

"Well, yeah. A lot of times." And like that, the floodgates open. The keep the conversation on Luffy and goofy stories of them hunting through the woods. It's a smart move as their newest brother warms up and never stops smiling about Luffy's stupid antics. It's the cheeriest lunch they've had in weeks and Marco feels something settle in his chest. This is where Ace belongs. This is how he fits into the crew.

Unfortunately, lunch ends on a stroke of terror.

"Yeah, Luffy's hat is his biggest treasure. He got it from his soul-father, Shanks." He leans back with a smile as if he hasn't broken Marco's world. "I still have to thank that man. He lost his arm saving Luffy's life. I can't ever repay that." The look on his face is so fond, brushing away the brief flash of 'what-if', that Marco can't even find it in himself to be furious. Akagami is going to have fuel to taunt him with for life but knowing how important Luffy is to Ace, how pivotal Luffy's survival was for his soulmate…

All Marco can feel is resigned. Damn Akagami was right. His soulmate is going to rock the world and had already started with Marco's own soulmate.

"He and Shanks made a promise that he'll give the hat back when he's a great pirate. So of course, he's going to be King of the Pirates." Ace laughs in pure joy. "Damn brat. Has never even beat me in a fight but still thinks he can be the next king."

The next couple days are better. Ace still attacks Oyaji but he's opened up more, talks to the crew. He even asked if he could join in on some sparring with a bo staff of all things. He said that he and his friend had taught themselves how to fight with pipes from the junkyard. No one questions the sad smile that came with it.

Marco is bringing him soup after yet another dip in the ocean when Ace finally asks the question that's been eating him. "You guys… why do you call him Pops?"

Marco cocks an eyebrow but answers honestly. "Because he calls us his sons. We're hated around the world, yoi. But we're happy. Words like these make us happy." And Marco remembers – with a searing clarity he wishes he could ignore – 'Son of the Devil' imprinted on his hand. Ace has a problem with his father. They've all known that. But whoever his father is or was, they all know that this is meant to be his home and Whitebeard is the greatest father in the world.

They next day, Ace takes the mark across his shoulder blades and the word Finally in Marco's familiar narrow writing stands out on the top of his left shoulder. Marco has to catch his breath for a moment. That's two huge gestures in one and Marco can't fully wrap his head around the staggering acceptance of not just the Whitebeard's, but of Marco himself.

At forty-five Marco finally has his soulmate in his life. Not as a kid, not as a student, but as a friend and comrade. He wasn't a big believer in soulmates but in their case, he thinks the universe got it right.

~Omake~

Ace is drinking with Marco and the other commanders when Thatch grabs his metaphorical balls and asks who Sabo is. Eyes purposefully dropping to the infamous tattoo.

Ace gets a distant look in his eyes and lowers his mug to the bar top. The silence drags and just as Marco is about to steer the conversation in another direction, Ace answers. "Sabo was my brother. He was my very first friend, back when I was five." His smile is soft, yet bitter. Was his brother. "He was my best friend. We taught each other how to hunt, steal, rob, build… Hell, we taught each other how to laugh."

He goes silent again and no one wants to break the moment. Marco had been sure it was a memorial from the beginning but he hadn't considered this. When the word 'BROTHERS' had come up on his hand he had thought it was 'We're brothers' not 'I have brothers'.

Finally, Ace starts again. "You know, Sabo and I kept each other going. Goading each other on, watching each other's backs… When I told Sabo about pirates, about freedom on the seas, it became both our dreams. He wanted to write a book about all his adventures, all over the world." He raises his arm ever so slightly to draw attention to where Sabo's memorial is written on his skin.

After a minute, Thatch breaks the solemn silence. "What happened?"

Thin lips pull into a hard frown. "Sabo's dad came to get him. He was a runaway noble and when his dad found out he was alive and living in the trash heap, he wanted his heir back. We kept Sabo with us in the treehouse after that but we needed supplies… Long story short: Sabo's dad got a hold of him, shit went down in Grey Terminal, and before I could grab Luffy to go rescue him, the idiot had tried to sail out on his own and got blown up by a Tenryuubito."

Marco shares a glance with Izo. That's a lot. It's a very abridged version of what they know was a horrifying experience that ended in fire and a man dead. But that was ok. Even with one brother lost, he had Luffy to pull him out of it and now he has a whole ship full of brothers.

Thatch throws an arm around Ace's shoulders in solidarity. "You know I ran away from being nobility myself." Ace gives him a wry eyebrow so Thatch nods solemnly. "Yup. Back when I was fourteen. I just couldn't stand all their rules and backstabbing – disgusting people."

For the first time since Sabo was mentioned, Ace cracks a smile with a mischievous glint. "You must have been pretty slow then. Sabo figured that out by the time he was five."

Thatch gives a comical double-take partly out of surprise and partly to lighten the mood. "Five!? What kind of five year old decides to run away? Shit, at five I barely knew how to count."

Ace's smile becomes more genuine. "The kind who values freedom. Sabo was a genius. It's why his parents pushed him so hard but he was still never good enough. Their loss though. Sabo belonged with us down in the trash heap."

"You lived in a trash heap?" Haruta latches on to the detail like a shark that's smelt blood. She's been starving for information about his past since day one and there's no way she's letting an opening like this slip by.

"Well, not really. I lived on the mountain with bandits but Sabo carved out a place for himself in the trash heap. We spent our days running around both and collecting out own 'Pirate Fund'. Then once we had Luffy we built a treehouse and that was that. We even made out own pirate flag." His smile is so warm with fond remembrance that Marco finds himself smiling as well. He's glad that his brother's death hadn't soured all the fond memories they had together.

The rest of the night slides by in a steady stream of laughter, beer, and childhood antics from all of them.

And… Scene.

You know, I was gonna put in a second omake about Shanks actually learning he was right but it just wouldn't come together and it's probably a lot funnier in people imaginations.

I had a lot of fun with this one. I love soulmate!aus and I found this unique soulmark setup in a Case Closed fic (DCMK Case Files by astorii on AO3, chapter 6) and I just loved it. It's not as invasive but can still tell you a lot about your soulmate. I originally wanted to apply it to the ASL Bros but then they would know Sabo is alive, and, well, that just kills the angst. Since I also ship Marco/Ace I decided they were the next best set. This didn't exactly end in a romance but you can read it either way.

Thank you all for reading and (hopefully) enjoying! Let me know your favorite parts, how you like this soulmark structure, and your ideas on how annoying Shanks is going to be. Criticism is also welcome!