This is for the Secret Santa collection for 2017. I had so much fun writing it, but when finished, was too scared to post it. I suddenly was not confident in my writing ability. But after I let a friend read thought and she loved it, it gave me the courage to post it. Hope you all enjoy it:)

"Let's see, where is it?" Dean mumbled to himself as he looked at the vast blackness of space. Where could this world be?

Dean Ambrose is a Keyblade warrior, chosen by the blade to save the various worlds from the threat of the Heartless. They're creatures of pure evil, born from the darkness of people's hearts. They've been destroying countless worlds, and Dean has been tasked to stop them and save those realms trapped in the Realm of Darkness.

His next stop, the aquatic world of Aerithia.

He eventually spots it and blasts off at high speed. He loves this airship Natalya crafted for him. It was a gift for saving her world of Ironhaven. He ended up there after his own world, Isle of Fate, was destroyed by the Heartless.

He landed the ship at a small beach. After emerging from the ship and looking at the vast ocean, he noticed a glow around his legs. When the light disappeared, he was shocked to see his legs gone and replaced with a gray mermaid tail.

Admittedly, he should be more shocked than he really is. But he's not too bothered with it. He figured it was the world's magic or something to help him on his quest.

Besides, it would be cool moving around the water with a mermaid tail.

Shrugging the change off, he hopped into the water and quickly adapted to the new fins. He figured out how they worked and swan deep down, looking around at the beauty of the undersea life.

But it was cut short when he noticed a group of Heartless surrounding someone. He materialized his Keyblade and charged ahead.

"Thunder!" he called as a small thunderbolt shot from his weapon, hitting one of the monsters. He slashed at the other two before floating protectively in front of the wounded merman, watching as the Heartless faded away.

"You alright?" Dean asks, smiling as he turns towards the other merman.

"Y-Yes. Thank you." he smiles. "They had me outnumbered there." He then frowns as he spots something in the distance. "More are coming!"

"Can you fight?"

"Yes."

"Then lend me your strength. We can talk more afterwards."

The merman nods and picks up a spear Dean guesses he dropped earlier in the battle. They stood side by side as the small invasion approached them.

As they engaged in battle, Dean was surprised how well this merman fought. He's good with a spear as well as the small amount of magic he seems to have. Also how…charming he is…

After the creatures were disposed of, and the weird thoughts Dean had about this stranger, the two moved to a safer location to introduce each other.

"Thank you very much for your help." the merman smiles.

Dean blushes lightly, "Your welcome mister…"

"Roman. Roman Reigns. What's your name? I don't recall ever seeing you around here before."

"My name is Dean Ambrose. I'm from another world." he answers simply.

Roman's eyes widened in amazement, "Another world?! How did you get here?! What are you doing here?!"

"Slow down dude." Dean laughs. Roman's excitement is too cute. "I got here by airship and the reason I'm here is to solve the issue of the Heartless."

"Those creatures you mean?"

"Yes. They're attacking all the worlds."

"Why? And who's ordering them to attack?"

"Still trying to figure that out honestly. All I do know is that they're looking for the Keyhole. All the worlds have one and within it lays the heart of the world. If the Heartless get inside and destroy the heart, the world itself will be destroyed and sent to the realm of darkness. It's happened to my world and countless others. My goal as a Keyblade warrior is to protect the remaining worlds as well as save the ones lost in the darkness."

"Wait, your world is gone?"

Dean nods sadly.

"I'm so sorry." Roman frowns.

"I…I was so powerless. Even with all my strength, the world was gone. My friends…they're out there somewhere. They're not in the darkness, I know they're not. They've got to be around.

Roman slowly approaches Dean, awkwardly pats his shoulder. Even though it was odd, Dean found it comforting.

"I'm sure they're somewhere Dean. Don't give up the search. I would like to help you on your quest in finding the Keyhole. My father, King Sika, rules the kingdom. He should know where the Keyhole is. I can take you to him."

Dean nods, "Thank you, I appreciate it."

Roman smiles and leads Dean through the vast ocean towards the kingdom, encountering more Heartless along the way.

They eventually reach a small city, filled with mermaids and mermen swimming around to various stores and such. They get to a large golden castle with two guards in front of the entrance.

"Halt!" one called.

"Don't worry." Roman smiles. "My friend and I seek an audience with the king. It's urgent."

The guards look at each other before nodding their heads. "May your meeting go well."

"Thank you." Roman nods as he takes Dean into the castle.

"So, you're a prince I'm guessing?" Dean chuckles as they make their way to the audience room. He didn't really look around, more focused on getting to know Roman more.

"Yeah. Only child and heir to the throne."

Dean ponders that more as they enter a large open room. At the other end sat the king in a throne. Dean noticed his face looked aged, like you can tell he's old. There were faint lines on his forehead, a black mustache that framed his mouth and his chin a little bit, a large nose as well. His tail was a bright red with gold designs and a paler red, borderline pink, fins.

"Who have you brought to me my son?" the king speaks in a deep voice.

"This is Dean father." Roman starts. "He seeks an audience with you."

Sika sits up, reaching for a long sword that was in a pedestal beside him. The sword itself was very basic: a long silver blade with some red and yellow gemstones along the hilt. "State your business."

"I have come to assist you with the incoming Heartless." Dean spoke. "They're looking for the Keyhole to send this world into the darkness. I'm here to seal it before they can get to it."

"The Keyhole you say?" Sika muses. "There is no such thing here."

"But father-"

"IT IS NOT HERE!"

"Sure it is." Dean says, not fazed at all with the king's outburst. "Every world has one. It holds the heart of that world. If those creatures find it and destroy it, this world will be destroyed and end up in the Realm of Darkness."

"And how do you know of this?"

"My world was destroyed. They came and sent the world into darkness. I was sent to another world during the chaos and learned of my mission. I cannot let any more worlds be destroyed like mine was."

The king sits there in silence for a long moment, staring right at Dean the whole time. "Leave at once."

"Father!"

"I will not ask again. Leave my sight at once! Roman, escort him out of the world and stay out of trouble."

Roman growls, taking Dean's wrist in his hand and swims out of the city. He takes Dean to a small cave some ways away from the city.

"Where are we going Roman?"

"My secret spot." the other merman smiles as he pushes a large boulder out of the way for them to enter. "I usually come here to escape. If I'm upset, coming here calms me."

Dean smiles as he follows after Roman. They literally just met and he's showing him something personal. It warms Dean's heart that Roman trusts him like this.

He looks around in awe, it's so beautiful in here. There were some shells decorating the floor, and a hole in the ceiling acting like a skylight, letting the sunlight from above cast a light into the small space.

"It's so beautiful." he whispers. "How did you find this?"

"Just stumbled upon it one day while exploring." Roman chuckles. "I never tire from seeing the beauty in here. It's so calming and it eases me."

"Light is a powerful thing." Dean murmurs. "Can't imagine why anyone would want to extinguish it."

"Extinguish it?"

"I think someone is sending the Heartless around to send the worlds into darkness, pulling them away from the world of light. Maybe, they're trying to get rid of light altogether..."

"Don't worry, we'll protect it." Roman smiles as he wraps an arm around Dean's shoulders.

Dean blushes as he leans into Roman's embrace. "Thank you Roman." he sighs contently.

"No problem Dean." Roman whispers. "Hey, you said before you were looking for your friends. What do they look like?"

"One of them is a male, names Baron. He's tall, black hair, some colorful tattoos on his chest and shoulders. The other is a female named Renee. She's sort of tiny, short blonde hair, light brown eyes, usually bubbly and outgoing."

Roman ponders his words, "Never saw anyone by those descriptions here, but I'm sure they're somewhere Dean. Don't give up."

He nods as he surveys the cave, spotting something against the back wall. He leaves the warm embrace to inspect it. "What's this?"

Roman follows in confusion. "Not sure. Never noticed it was there before."

Dean touched what looked like an emblem, finding a crevice that looked like a sea turtle. "Seems like a stone goes here."

"Let's search for it. Could lead to something."

Dean nods and they leave the cave to start the search.

After an hour of searching and finding nothing other than Heartless, they come across a sunken ship.

"Must have sank last night, wasn't here before." Roman comments.

"Let's check it out. Maybe the stone is there."

The two carefully swim towards the wreck, but unfortunately attracted the attention of a shark.

Roman noticed quicker than Dean did and blasted the dangerous animal with a water spell.

"He's mad at us for invading his territory." Roman spoke.

"We will only be a short while." Dean reasoned, ignoring the fact that Roman seemed to know why the shark was bothering them. Could be a guess though, but still.

"It doesn't matter to him. We're in his home and he doesn't like it. We either leave, or we become food."

Dean sighs, materializing his Keyblade as Roman gets his spear.

The shark lunged at them, the two quickly dodging as Roman hit him with another water spell. Dean whacked the animal a few times, enraging him more. Dean wasn't fazed and continued his attack until Roman hit a sleep spell on the shark, quickly putting him to sleep.

"That should buy us some time. Let's hurry."

Dean nods and the two enter the ship.

It was pretty barren. Just a couple of crates and loose items laying around. Shouldn't be a problem spotting the stone.

Dean was in the middle of trying to open a crate when he hears Roman shouting.

"I found it!"

"You did?!" Dean quickly follows Roman's voice to see the stone.

It was a light gray stone that was shaped like a baby sea turtle, just like the emblem.

"Wonder what it was doing on the ship." Roman pondered.

"Maybe the ship was a trading ship and the crew were hoping to get money from it. But it doesn't matter now. We found it and now we need to get back and put it in the emblem."

Roman nods and the two leave, quickly swimming back to the cave.

But when they get there, they see King Sika by the entrance, along with two guards. Without any warning, Sika shots an energy beam from his sword, aiming for the stone in Dean's hand. Dean was able to turn his body enough to protect the stone, taking the hit in the process. He screamed in pain as he fell to the ground, clinching his shoulder. Roman was right at Dean's side, glaring at his father.

"Father! What is the meaning of this?!"

"I told you to get this menace out of our realm." the king replied.

"I can't father. Our world is in danger. We need his help."

"What help could he possibly be? He's the reason those damn creatures are even here to begin with."

"Bullshit!" Dean spats. "The Heartless were attacking other worlds long before I became a Keyblade warrior! How do you think my world was destroyed?! My friends are missing because of them!"

"…You need to leave."

"Not until I seal the Keyhole!"

Sika growled, "I told you th-"

"Bullshit! I sealed at least four at this point! They do exist!"

"…That Keyblade brings nothing but trouble."

"You're wrong father." Roman interjects calmly. "The weapon is a symbol of light, of hope. It has brought salvation to countless worlds, it doesn't bring destruction and calamity. We need to use this weapon to protect our world from these creatures father. Don't you want this world safe?"

Sika sighs quietly, turning his back on his son and the Keyblade warrior. "Make sure he's out of here by day's end, or I will eliminate the menace myself. He's not welcome here." He then swims away, leaving the guards to block the entrance to the cave.

Roman growls and takes Dean to a safe place.

"Dean?"

"Hurts.." Dean manages. "Surprised I was able to form complete sentences back there. My cure spells are too weak to heal this."

Roman panicked, "I can go into the city for potions for you."

"That won't be necessary."

Roman and Dean both looked around in shock, finding the source of the voice swimming up to them.

It was another merman, slightly younger than Sika, but older than both Dean and Roman. He has a shaved head and beard, well-toned chest, green tail with paler green fins.

"Who are you?" Dean groans.

"Hunter." Roman answers for him. "What are you doing here? Father will smite you if you're so much as glanced."

"Worry not, I won't be here long. But it seems your friend needs help. Come with me, I have something that will cure him."

Without hesitating, Roman picks up Dean and follows Hunter to his lair. It looked like the skeleton of a dead fish, which made Roman a little uneasy. But he pressed on. He needs to help Dean.

They made their way to a large room with a caldron right in the middle. Potion bottles scattered around the room, a spear and sword hung along one of the walls.

"Now then, lay him down on that table over there while I try to remember where I put that cure potion."

Roman nods, laying Dean down on the table as instructed. "Dean?"

"Ro, you sure you can trust him?" Dean whispers.

"It'll be fine. He used to battle alongside my father." Roman whispers back.

"Ah, here it is!" Hunter announces triumphally, picking up a bottle with blue liquid and swam over. "This should help."

Dean was cautious about this, but he didn't have much of a choice. He slowly took the bottle and drank the strange substance. He felt the potion work, feeling a lot better.

"Wow, that stuff works! Thank you." Dean smiles.

"No problem." Hunter smiles. "Now that you're okay, there's something I want to talk to you two about."

"What is it?" Roman asks.

"I have a suspicion that the Keyhole is in the palace." he starts.

"You mean my father's palace?"

"That's the one. It's just a guess of course."

"Wait, how do you know of the Keyhole?"

"Oh, it's a tale as old as time boy. A world's heart is protected within that lock."

"Then why is my father being stubborn by saying it doesn't exist?"

"Because that's just who he is. He's always been stubborn and just irritating. Thinks he's always right and challenges anyone who defies him. That's why I left the army, couldn't stand him ignoring my battle plans and attempts to help out. But going back to the matter at hand. I would like to make a deal with you."

"What kind of deal?"

"You get me into the palace and I'll help you search for the Keyhole, as well as make your greatest wish come true."

Roman's breath hitches, "My…greatest wish?"

"But of course. I know you want so desperately to see other worlds. To learn of different ways of life and to explore new areas than the same boring waters here."

"Ro?"

"He's right Dean. I want so badly to see other worlds."

"And I can help with that. I just need your father's sword. That has enough power to help you get to those worlds."

"Hunter, is the sword really capable of that?" Dean asks, not fully believing Hunter's words. That sound too good to be true.

"Yes it is. It's the most powerful weapon under the sea. It can do anything except bring back the dead. That skill never works out well to be honest and it always messes things up."

"So, you need the sword to help me get out of these waters?" Roman asks.

Hunter nods, smiling.

"I'll do it."

"Ro!"

"Dean, we need to do this. Besides, we can locate the Keyhole too. Then we can get rid of the Heartless and I can travel to other worlds with you." Roman then motions for Hunter to follow him as the two head out of the lair

"Ro wait!" Dean calls as he swims after him.

He continues to try and get Roman to stop, but his calls are ignored. Dean doesn't believe a word Hunter said before. Sure he helped him, but something is defiantly up with that promise.

When Dean makes it to the palace, he discovers that's it's swarming with Heartless and the guards are having trouble against them. He gets his Keyblade out and fights the monsters.

Please be alright Ro…

Once the Heartless were disposed of, Dean quickly hides before anyone spots him.

He's still worried about Roman. He still thinks Hunter is tricking him with the whole deal. Does he really need the sword's power to get Roman to the other worlds? It just seems like an impossible thing. Then again, he himself is able to go to other worlds so it's not too impossible then. But Roman's a merman. He would need to change his whole existence to travel outside this realm.

As he thinks more on the idea, he spots the very person he's thinking about swimming away from the palace. He quickly swims up to have, calling his name.

"Ro!"

"Dean?" Roman questions as he meets Dean halfway.

"Where's Hunter?"

"Still in the palace I think."

"Why aren't you with him?"

"Was dealing with the Heartless myself. Had no idea they were here."

"We should check around. See if he's still in the palace."

Roman agrees and the two go back inside and search around. But when they got to the audience chamber, they noticed Sika wounded on the floor.

"Father!" Roman called as he and Dean both swim up to him. "What has happened?"

"Hunter…was here." Sika grunted. "He took the sword, attacked me and fled with it. My men tried getting the sword back but failed as well. We have to get it back. The faith of Aerithia depends on it."

"Don't worry father, I'll retrieve it for you. Come on Dean."

Before another word could be spoken, the two merman quickly fled the palace back to Hunter's lair.

"Why would Hunter harm father?"

"Why do you think? He wants to rule the realm. My guess is that the wielder of the sword is the automatic ruler."

"I…I let this happen..."

"Stop. You were blinded by a desire that Hunter exploited. Can't change the past, but we can fix the present so the future doesn't suffer."

Roman smiles over at Dean, "Thank you. Now come on."

They soon enter the lair, getting to the large room from before.

"Show yourself Hunter!" Roman shouts into the empty space.

"I should thank you for allowing me to acquire this." Hunter smirks as he emerges from the darkness. "After all, I now rule this world. And I did promise you something, I am a man of my word after all."

Dean wastes little time and lunges at Hunter with his Keyblade, Roman joining him with his spear. But Hunter was quick to defend and blast them into separate directions: Dean crashing into shelves with empty bottles while Roman went through a table.

"Now then, my promise." Hunter smirks as he fires a white energy beam at Roman, which engulfs him in a ball of light.

Dean growls and lunges once more, but Hunter pins him to the wall, the sword laying across Dean's throat.

"Some Keyblade warrior you are." Hunter taunts as Dean struggles. "You know, you are pretty cute. It's a shame you have to die for darkness to rule."

Dean's Keyblade suddenly starts glowing a bright white. "Not…today.." he grunts as he blasts Hunter away with the glowing energy.

Hunter slams into the opposite wall, clinching his chest. "This isn't over." he states as he teleports away in a puff of black smoke.

Dean slides to the floor, panting as he looks over at Roman, who was now unconscious from the light. But…it's not Roman the merman anymore. It's Roman…the human. Hunter's blast turned Roman into a human.

Shit.

Dean quickly grabs him and swims up to the surface. When he breaches, he carries Roman to the shore, laying him in the sand.

"Ro?" he calls in worry as he leans close to his friend.

Roman groans as he slowly wakes. "Dean?"

"You okay?"

"...Sort of?" He notices something wrong. He doesn't feel his tail. He looks down, shocked to see his tail is replaced with legs. "Wha?"

"Hunter. That blast transformed you."

Roman's eyes widened as he studied the new limbs. "O-Oh my goodness…"

"Ro?"

"I'm…shocked. Didn't think this was what Hunter had in mind."

"Speaking of him, we need to find him and get the sword back."

"But with me like this, I can't swim. I have no clue how these things work."

Before Dean could say anything, there were loud rumblings coming from the water. The sky darkened from a light blue to a dark purple as Hunter, now giant in size, rose from the water.

"…Not good." Dean mumbled.

"How are we going to fight him? We were weak against him before."

Dean looked around, noticing a boat some ways away on the shoreline.

"That's how. You fight on that boat while I handle the water stuff."

"But Dean…"

"No buts. We can win this."

Roman smiles, nodding his head. "Can you bring me over there?"

"Of course."

Dean helps Roman to the boat, getting it in the water before approaching the giant Hunter. Roman watches in worry as Dean swings his Keyblade at Hunter, concerned about his safety.

Why is he going on this journey alone? He should have people with him. To help him against enemies like this.

He smiles as Dean was able to knock the sword out of Hunter's hands, which lands in Roman's boat.

"You'll pay for that you little shit!" Hunter calls as he reaches into the water and pulls a struggling Dean out.

"Let him go!" Roman calls in a panic, taking the sword in his hands.

"Give me the sword and I'll release him."

"Ro no!" Dean pleads before crying out in pain.

"You want it? You can have it." Roman smirks as he throws the sword at Hunter's abdomen, watching as it pierces right through him. Hunter screams in agony as he quickly sinks into the water, fading into darkness. Roman sees Dean falling and moves the boat over to catch him.

"Thanks." Dean pants as he smiles up at Roman.

"Thank goodness you're safe."

"Some hero I am though."

"Hey, even heroes need allies."

Both miss Sika emerges from the water, collecting his sword as he watches the two while quietly reverting Roman back to a merman.

The evil has been vanquished.

After the grueling battle, Sika takes Roman and Dean back to Roman's cave. Sika admits to them that the stone would have revealed the Keyhole and he tried destroying it to prevent it from being found.

"I'm sorry for giving you a hard time before Dean." Sika apologizes. "I was just wary about you and wanted to protect the kingdom."

"It's alright sir." Dean assures. "I understand where you were coming from."

When they got inside, Dean hands the stone to Roman to place in the emblem. Once done, a faint image of a keyhole appeared over the emblem. Dean takes out his Keyblade and points it at the lock. A white beam emerges from the weapons and hits the lock, causing it to fade away while making a locking sound.

Task complete.

Roman and Sika follow Dean to the surface to see him off. Sika looks at his son, frowning as he senses something wrong.

"What's the matter son?"

Roman sighs, "I…I want to go with him father. I want to see all the worlds he's going too. I want to help him fight those monsters. I…I want to protect him father."

Sika sighs, "Is that what you really want to do?"

"Yes. I want to keep him safe. He's the light for all the worlds out there."

Sika smiles, knowing there's a deeper meaning to Roman's words. His son is in love and what kind of father would he be if he didn't let him pursue it? Using his sword, he grants Roman his wish. "Go my son. Protect the last light."

Back on the ship, Dean is happy to see his legs again. Although being a merman was fun, it's nice to walk. As he's getting the ship on it's next course, he hears a familiar voice call his name.

"Dean! Wait!"

Dean looks over to see Roman, back in human form, crawling into the ship.

"Roman?" Dean questions as he rushes towards his friend, getting him into a seat. "What…What happened?"

"Father turned me back so I can travel with you." Roman blushes.

"You…want to come with me?" Dean blushes back.

"Yes. I want to help you on your quest. I can hold my own in battle, I won't be a hindrance. Please Dean."

"…Okay." Dean smiles brightly. "But we should get you used to using human legs. Let's go to Ironhaven and practice a bit. Nattie can help with that too."

Roman nods excitedly, "Let's go!"