Mehehehehe. I never expected to get so many follows so soon. Originally I was going to post this after my midterms, but I stress wrote, so I guess it's ready to post. Might be rushed but oh well. I added quite a bit of exposition here, which I hate. A story isn't a story if it's pure exposition. I tried to reduce as much as I could so I can write it out later.

Oh, also this was my first story here. I forgot to add something to ch 1 and frankly editing it looks like a nightmare, so I'm posting it here.

Tsuna stared in awe at the man who saved him. He was dazed from the pain but he could make out hair as red as fresh blood and a pretty blue light.

It happened so suddenly, a flash of light and then the man who hurt him was gone, replaced by this man who held him gently in his arms.

This is the first time Tsuna has ever felt safe, a familiarity with the man not shared even with his blood mother.

'Is this what a father feels like'

Bitterness creeps into his heart. This complete stranger has done more for him than anyone else. Why can't he be his real father? Why was this man not in his life before? Why can't he have this for himself?

The man says something with desperation laced in his tone, but Tsuna is dizzy with the pain and doesn't understand a word coming from his mouth. All he knows his his little hand clings onto the older man's hand who doesn't resist. It makes Tsuna feel warm, as though he feels a connection with this man.

Soon it feels like he is flying, with the wind rushing through his hair and caressing his skin. The cold night air feels good on his flushed skin, still hot from all the blood searing hot against his injuries.

He closes his eyes, at peace with himself for the first time since his father and some old man came home and promptly faints as the pain finally catches up to him.

Shirou Emiya was scared, scared for the little boy he held in his arms. He was almost too late to save him. He was lucky he smelled the faint scent of dormant magic in the boy. It smelled of freedom, of fresh clean air found in the deepest of forests free from civilization. It smelled of heat, of fire hotter than the hottest of forges. It smelled of home, of a time long ago where he and his beloved Rin were surrounded by friends and family.

Shirou arrived at the nick of time before the apostle fed and killed the boy. Sadly, the boy was still hurt, nothing fatal but it broke his heart seeing a child endure so much pain.

His heart clenched seeing the tentative smile on the boy's face, a smile that reminds him of his father Kiritsugu. It was a smile of relief and unparallel gratitude.

He tried talking to the boy, to find where he lived and where his family was, but the boy simply gave him a heavy lidded glazed stare. He must be exhausted seeing what he just went through. And it was so late at night. Why was this little boy out so late? Where are his parents? He didn't see any bodies with the vampire nor did he smell any blood, so maybe the boy lived on the streets. If the grime and tattered clothes were anything to go by this was likely the case.

Quickly he gathered the boy and rushed home. If anyone can help the boy it would be his wife. No one knew healing magic better than her. She did get a lot of practice thanks to him after all.

He jumped from building to building, disguised to all thanks to a portable bounded field Rin made on his belt.

It took nearly half an hour to reach his home in Fuyuki from Namimori. The two cities were close together, separated by the same forest Illya once chased them through with Berserker.

After the grail war he tried to follow his ideal, to become a hero who saves everyone, yet he couldn't do it. He nearly destroyed himself pursuing his dream, pushing everyone away and burdened himself with an impossible task. It was Rin who pulled him from his obsession, who reminded him he has something to live for other than his father's dream.

It killed him, it killed him knowing he could not save everyone, that he could not save the world. But he learned the hard way that the world was so big and he alone could only do so much before he ended up like Archer.

But throughout it all he had one constant, her. Rin. The love of his life. She always pulled him back before he fell into obsession. She was proof that even if the world could not be saved, at least the most important people to him could be kept safe.

He rejects the values of the Mage association, but admits associating with them while not joining them has a lot of benefits. He became an enforcer of sorts, not a dog attentive to their beck and call, but a freelancer who works on his terms. He hunts dead apostles for them, and any nearby Magus who he deems to conduct immoral research. He is their judge jury and executioner.

Magic is not the only thing he tasks himself to fight. He patrols the surrounding area at night in search of crime. Fuyuki and the surrounding area have the lowest crime rates in all of Japan thanks to him.

Rin occasionally joins him on patrols or his hunts for Dead Apostles saying she needs the exercise. When she stays home she ensures to have dinner prepared for when he arrives. Of course, she is never honest and constantly denies she was waiting for him, saying that he arrived just as she finished cooking.

It endears him knowing she hasn't changed from that highschool girl he fell for, one who's care and love is shown through her actions hiding behind a brash attitude. Normally he was in charge of cooking, but Rin refused to burden him on the nights he has to fulfill his responsibilities, saying 'I don't want to wait till it's the middle of the night before I can eat!' .

Unfortunately today Rin's efforts will likely go to waste.

Rin immediately knew Shirou returned home once he crossed the bounded field. His magical signature was easily identified and granted him passage. Yet there was a second magical signature that made Rin grow weary. While Shirou may have given up his dream, he is still an optimistic fool who easily trusts others, even magi. She loves her husband and knows he is strong, but sometimes she can't help but curse his altruistic heart that helps anyone who asks for it.

Rin opened the door to confront her husband.

"Shirou! Why did you bring a magus here this late-!" She froze when she saw the body of a young boy no older who looks no older than five in shirou's arms. All previous thoughts and reservations were forgotten as concern filled her gaze seeing the state the boy was in.

He was pale faced with tear tracks staining his cheeks. His body was littered with ugly bruises and scrapes, he smelled of fresh blood despite the only blood evident being dry.

She doesn't trust magi, even children could pose a threat, but seeing this boy just made her feel pity for him.

"What happened to him?"

"A Dead Apostle attacked him. He was all alone in an alleyway. Bastard hurt the kid without breaking the skin. There were no signs of anyone else in the vicinity. I think he may be an orphan. He looks underfed and dirty, as if he was living off the streets for a while"

At this point she lost all reservations. Upon closer observation she saw it was true, the kid was dirty and covered in a fine layer of grime. His clothes were barely more than scraps of cloth and he was thin as though he was underfed for months.

She felt sympathy. Both her and Shirou were orphaned young as well, but they had access ro resources and people to rely on. Shirou has Taiga and she had Kireii. At least he fulfilled his duties.

But this child had no one, something she couldn't imagine.

"Shirou, take him to the bath. I'll heal him while you clean him. That way he doesn't dirty the house."

Of course that was just an excuse. The house can always be cleaned later, but cleaning the boy would remove some discomfort when he awakens.

Shirou rushed to the bath while Rin trailed after him, lost in thought. She and Shirou felt responsible for all magi in Japan, to regulate their activities and to protect them if the need arose. Her pride as the second owner of Fuyuki broke seeing how Shirou of all people evaded her detection.

Her burdens were Shirou's, just as much as Shirou's were hers. She quickly made damn sure to memorized every magus in vicinity. As far as she is concerned with it is simply expanding on duties as second owner of Fuyuki.

Yet thinking about it, she has no clue who this boy was. He wasn't a registered magus, yet he had active magic circuits. Curious. Very curious.

While Shirou bathed the boy she healed him and performed structural analysis to check his body, to ensure nothing abnormal remained. What she initially found was shocking, but as she kept analyzing she was left dazed with the impossibility before her.

"Rin?"

She stared dumbly at the boy, at the immense power he holds and turned to Shirou licking her dry lips from the nervousness.

"Shirou, I think this boy is a child from the mafia."

"What?!"

Shirou looked at the little boy, and stared back at his wife with an incredulous look in his eyes.

Slowly, as if he was afraid Rin would lash out, he tried to reason with her.

"Rin, look at him. He can't be older than 5, 10 at most! How can a little boy be part of a criminal organization?"

Rin was exasperated at her husband's ignorance. She forgets that despite his immense power he knows little about magecraft and magic society.

"No, he's not a killer for the mafia like you think. He was born into the mafia."

Shirou tensed and an angry glare came to his eyes as he snarled out an unpleasant thought, "Did they abuse him, left him alone to die in that alley?"

"Shirou, you may not know this, but upper level mafia members have magic circuits."

And so she explained how the mafia and their silly rainbow flames were well known to magi, afterall their flames are a form of very low quality magecraft.

They were something unique, possessing physical magic circuits. When magi discovered this they grew excited at the opportunity to strengthen their craft, yet the excitement soon dampened when they realized these circuits were of the most pathetic quality possible.

Each magus, even a third-rate one like Shirou, is capable of drawing mana from the world to power spells, or in Shirou's case convert it into Od if there is a necessity. But the circuits common in the mafia are unable to do so.

Instead, each of their circuits only generate a pitiful 1 unit of magical energy. It was beyond pathetic. As the average number of circuits is 20, at best most can generate only 20 units of energy.

This severely limited their spells, and what spells they did create were of no interest to magi. For example, one of their common spells, a 'rain flame' that produces sensory deprivation to induce an artificial state of calm, has no effect on those with higher magical energy. A rather weak magus of 15 circuits producing 10 units each for a total of 150 units is unaffected by them. A weak hypnosis is stronger than that. Same goes for their disintegration spell. It is as though simply having a little bit of magic grants magic resistance to the point of immunity against them.

Sure the concepts behind the spells were interesting, but there already existed spells for their effects. Reinforcement and hypnosis being two of the most common variations of their spells. Besides there was no use in such fragile spells.

Some magi were still interested in the phenomenon of physical circuits, but after decades of experimentation there was no known cause for this, and frankly many magi decided to focus their research in other endeavors save for one or two stray magi interested in them.

Their discoveries disheartened them even more, to the point they shared their research as they gave up. Apparently there are seven variations of circuits, with the rarest of them being called 'skies' and are capable of at least using a bit of mana, and most are born with only one type of circuit. Each type of circuit is limited in the type of magic they can caste.

Attempts in breeding magi with members of the mafia also yielded no results. Every child lacked spirit circuits from their magus half, and carried only the deformed physical circuits of average count. Homunculi couldn't be made from them as they lacked the sufficient Od and the ability to gather mana to sustain them.

The magi gave up as the mafia showed no promise in helping them reach the Root seeing how damaged they were. For the most part the Magus Association and Church left them alone.

Most magi laugh at their antics, as they believe they were the secret society hoarding the secret to infinite power. So long as they kept magic a secret from the populous, they didn't care about their activities. There are plenty of cases where they nearly expose themselves. Luckily they are rather small and easily dealt with, but should the mafia ever do something overt that threatens their secrecy, well it wouldn't be difficult to eliminate them.

"But the kid has very potent magic. I felt it! How can he be of the mafia when he has strong magic!"

Shirou knew how it was to be underestimated, and he would not underestimate any member of a society composed of cold blooded killers. In many ways they were worse than magi. Their sense of superiority gives them justification to commit heinous crimes, simply because they had the power. They raped, kidnapped, enslaved, killed, and stole far more often than any magus would do. At least magi have a reason to do what they do. They commit crimes only for the sake of research, never for the sake of crime itself. Criminals like them were part of the reason why he gave up on saving everyone, as many of them do not deserve to be saved.

Magi focus on the Root and neglect development of technology, but the mafia, despite having weak magic, are bound to have found ways to incorporate both together. It was one such reason why Kiritsugu was feared, because he used technology to his advantage. At least the magecraft of the mafia wouldn't affect magi much, making them slightly less of a threat with that avenue cut off.

"I don't know how, but he has more than the average number of circuits, a lot more. 168 to be exact. 21 circuits of each variant of physical circuits plus 21 spirit circuits of 49 units each. What's strange is that someone tried to block his circuits in a poor attempt to deactivate them. Frankly I've never seen anything like this, but it was easily removed by flooding his system with mana"

Now Shirou didn't look at the boy in his arms with shock at his power, but concern. It's obvious based on what Rin said, the boy was blessed with power, but that blessing is a curse in disguise. If his abilities ever got out magi association would place a sealing designation on him much like they would should they discover he himself has a reality marmana. Whomever attempted to disguise the boy failed miserably as those attempts were likelier to harm the boy than actually disguise him.

This boy was a miracle, the actualization of something magi can only dream of. Something they would kill to get their hands on.

Not only does he have high quality circuits with a high circuit count, but most of them are physical, making them far more potent than normal circuits that reside within the soul.

In this day and age where mystery has been lost, this boy might be the key to restoring magecraft to levels close to true magic as it was in the Age of Gods.

"Rin, we can't, we can't hand him over to the Magi Association. He's just a kid, they would destroy him!"

"Shirou I know. I can't in good conscious hurt an innocent bystander like this. For now he stays with us. In the morn when he wakes up, we will talk to him and proceed from there."

The two kept silent as they held vigil over the boy for the rest of that night, unable to sleep both as they mulled over that night's surprises and as they waited for the boy to finally awaken.

Today Tsunayoshi thought he was all alone in this world, yet starting on this night he found two people who see him for who he is, who will love and protect him as they call him one of their own. Tonight is the last night he will ever think he was alone.

Why I chose that number of circuits: originally it was going to be 73, the sign of the trinisette, which makes 343, which is a bit too much for me. Instead I settled for 7+7+7, because there are 7 per sector of the trinisette. 7 vongola, 7 mare, and 7 arcobaleno. 21. Thus 21 for each flame type making 147. I also gave him an additional 21 spirit circuits cause I can. Each unit carries 49 units cause 21 would have been too low of a number, so 7x7. 7 is literally the magic number. Shirou is an anomaly, like our Tsuna, but generally there is a linear relationship between # of circuits and their capacity. It's still monstrous, but I wanted to make Tsuna's circuits be related to the trinisette and frankly this was the best I came up with.

Some rants:

Frankly I hate how most crossovers deal with secret societies. Some naruto crossovers have this 'veil' that hides the elemental nations. Not bad, but everyone in the elemental nations knows this, yet none of the expansionist powers there want to conquer the world? Learn the superior technology we have? Where rogue shinobi can go and flee? It would have been better if they themselves didn't know about the 'veil' cause frankly that premise is stupid.

Similarly I hate khr crossovers where characters like Reborn know about other powers like HP magic or something, yet they do not try to take and use these powers to their advantage. They act like bigshots knowing these other societies yet never showing this knowledge or power outside. Honestly it pisses me off.

That's why I think it's better if 2 secret societies are so secret that they don't know about each other or one society knows about the other but kept themselves hidden (The khr fanfic 'We weren't born to follow' by seito did this beautifully). You know what I chose, I mean considering how characters just scream out their existence, a baby hitman who pulls off unrealistic stunts, crazy not assassin like assassins that are the loud attention demanding Varia, mafia that doesn't even try to hide that they are mafia (like when dino brought a shit ton of men to Tsuna's home. Real inconspicuous).