Tada, another crossover for one piece and my hero academia! This one is focused on Luffy, Zoro and Sanji, the strongest best friend trio. There's a character death in this that I hope people won't hate me for, lol. I really had fun with this one, loving making characters not humans. The best! The three of them are pretty op later in the story. Luffy is a fucking little shit to the League, which was really fun to write lol. I did my best to keep the main characters in character. Some background characters might act differently.

This is a crossover, but I'm not marking it as one to see if it's the MHA fandom that only left the negative comments on my previous crossovers. I've never had so many comments that were just rude on any of my OP fics. I may end up taking this down if that's not the case. If I do, it's still up on ao3. PS: If you don't like the story or the way the characters are written, then please don't read it.

Shitposting for no reason is not welcome. Actual constructive criticism is appreciated, but it won't change anything since I always finish writing and editing my stories before posting them so I never risk leaving my readers hanging. Anyways, enjoy~


A baby slept in his stroller, snoozing quietly, thumb in his mouth and arm wrapped around a stuffed animal from his own world, which he'd just been transported away from, losing his amao, his mother. He was in the stroller being pushed down the street before he was suddenly here, his mother gone.

He was still asleep, as there had been no loud noise or startling movement. His stroller just easily went from one world to another. The person who might have summoned him was laying on the ground in front of him, though the baby didn't notice and continued to snooze. His tiny wings were pressed against his back, his stubby horns just barely poking out of his messy hair.

Luffy didn't know he was gone, someplace completely foreign and unknown. Possibly scary. Well, not scary yet. He was asleep even as the stroller was pushed somewhere else, out of the middle of nowhere with a dead body. The body of someone who seem to have used their quirk too hard with an unstable drug. It killed him, and if was him who'd done it, he was unable to put Luffy back where he came from.

He didn't wake up until he was laid on something nice and soft, opening his eyes and looking around, his thumb still in his mouth. He didn't recognize this place, but there were plenty of pretty colors to distract himself with. He saw some people looking down at him, one with pretty wings like birds.

He gripped the finger of the one with big hair and stuck it in his mouth, chewing on it with his gums. He cooed at the demon baby, while the one with wings looked conflicted. But when Luffy started crying, wanting his stuffed animal, and he was given it and stopped crying, the man's face softened and he gave the baby a smile.

-x-

The moment Marco came across the stroller, he knew what was in it wasn't human. His phoenix senses were telling him that whatever it was, was not human and was abnormal. Not necessarily dangerous, but unknown and foreign. He walked closer to it and saw a baby. Just a baby with tiny, stubby horns and wings.

His quirk could explain that, but the feeling he got from him didn't. But it was a baby. Couldn't be more than six months old, and Marco couldn't just leave it there. He called 110 about the villain's body, and said he had to go back to work immediately, but would call later.

As a pro-hero, this went by just fine, and he pushed the stroller back to the agency. The baby didn't stir, stayed asleep the whole time. Even though it gave off a not normal presence that was slightly concerning, he sensed nothing bad from him. When he pushed the baby through the double doors, he immediately went to the kids' room.

The Whitebeards were known for rescuing kids off the street and finding homes for them. That was why they had specific rooms for children to play in before any foster home was organized for them. Rarely, they kept the kids they found, like Ace and Sabo, who lived in the loft with Marco.

He got the baby to the changing room and saw his diaper was clean. He took off the shirt and saw he had little black spots on his stomach and chest. He pressed on one of them gently, but it didn't seem to hurt.

Thatch came in, asking about the baby before he saw him up close. "Oh my god. That is the cutest fuckin' baby I have ever seen," he gushed quietly. After moving his head to the side slightly, the baby woke up and started crying until he got his stuffed creature. Thatch wiggled his finger over him and the baby grasped it and pulled it to his mouth.

Thatch smiled softly at him and Marco couldn't help the smile that formed on his own face, too. "I'm sure he's not human," he said honestly. Thatch was shocked and looked down at him, now noticing the differences. But he asked how Marco knew in the first place. "The feeling he gives off. Plus the markings. I know they could be due to a quirk, but still. I don't think he is."

"So what do we do with him?" Thatch asked, the baby still chewing on his finger. Marco said he honestly didn't know. "We could raise him along with Ace and Sabo. I'm sure they'd both be happy to have a baby brother."

Marco was unsure, what if he was dangerous? But he didn't look scary at all. Maybe they could raise him as a human. The guy that somehow got him was dead, unable to use his quirk to send the baby back. "I think we should ask Pops first for sure," Marco replied. Thatch agreed, and picked up the baby, holding him against his chest, rubbing up and down his bare back.

The two heroes left the kids' room and found Pops in the meeting room, working over paperwork. He looked up and saw the baby, looking surprised. Marco shut the door behind them. "Find another abandoned baby?" he asked sadly. But he saw the wings, and looked curious. Wing quirks were rare. Marco had rare wings, similar to Hawks'.

Thatch sat at the table, cradling the baby. Marco sat next to him, looking at the tiny creature holding his stuffed animal that Marco didn't recognize. "Not really. I found him in a stroller by himself, but I don't think he was abandoned. I don't think he's human. I get a strange feeling off of him, and he has strange markings."

Whitebeard frowned, pointing out a quirk could explain his appearance, but the feeling changed things. "What do you think he is?" Marco said he had no idea. "What would you like to do?" the older pro-hero asked. He was the number two at the moment, happy with the position. He loved being seen as the hero who loves kids.

Kids were wonderful and deserved happy futures. "I want us to keep him and raise him alongside Ace and Sabo," Marco replied.

"Went after Blackbeard and came back with a non-human baby, huh?" Whitebeard said in amusement. "Very well. We need a pick me up and I'm sure a baby would do that."

The baby gripped Thatch's shirt and cooed, wiggling slightly. Thatch adjusted him in his arms. He started crying, probably hungry or peeing himself. Thatch went to check on him.

He hoped that he could eat human food or he'd starve. They'd start with water first. Oh, he hoped he'd be okay. Whitebeard said he trusted Marco, and if he felt it was safe for the baby to stay, he would respect that choice. Marco thanked him, and went out to Thatch to see how he was doing. Maybe check his clothes and see if he had a name.

Thatch was changing his wet diaper, humming while the tiny boy kicked his feet and giggled. Thatch was smiling, always having a soft spot for babies and toddlers. Ace and Sabo were in the other room, working on homework, both in sixth grade. Marco walked over and asked if he'd found a name on him.

Thatch said, "There's some writing on his pants, but it's in an unrecognizable language. But, the letters, if that's what they are, resemble 'Luffy'. So we should call him that."

"Luffy, huh? Well, we have a name for him now." Luffy yawned a big yawn and Thatch took him to the crib they had, moved to the office so Thatch could keep an eye on him, clean sheets for the next passing baby. Well, Luffy wouldn't be passing. They would bring one of the spare cribs to the loft where Ace and Sabo slept. They knew both of them would be so excited to have a baby brother, even if he didn't seem to be human.

They gave him water, but he didn't like the taste of it, so they got him some milk. He liked that okay, even if it wasn't milk meant for babies. Well, they had no breast milk on hand. Hopefully this would be alright. Thatch laid him in the crib and then went to the desk to work on paperwork and watch over Luffy at the same time.

Babies required a lot of attention, so he'd get used to this. After a while of Marco patrolling, he came back and found Luffy in the crib playing with a stuffed animal that wasn't his own. He cooed but didn't seem upset. He eventually fell back to sleep.

At dinner time, Thatch had formula he had Haruta go buy. They fed Luffy the formula, which he drank just fine, and then put him to bed in the loft where Ace and Sabo were. Thatch burped him over his shoulder, and when he did spit up, it made him laugh hysterically and thrash around in the man's arms until he tired himself out and put his thumb in his mouth.

Even if Luffy wasn't human, he was damn adorable and Thatch was excited to have him with them. When Ace and Sabo were told about Luffy, they were very excited, and when he was brought to the smallest room in the loft that Ace and Sabo didn't sleep in, they kept going in and checking on him, even if he mostly was asleep in a star onesie. So cute.

After the two and Marco went to bed, Marco heard a squeaky noise, like a newborn puppy, coming from Luffy's new room. Marco heard it first with his enhanced senses, and walked inside to see Luffy had transformed into a little furry black creature. He looked like a winged dog with horns, longer than they were in his first form. He touched Luffy's furry tummy, now knowing for sure he wasn't human.

He sqeaked and tried standing up. He was clumsy, but managed and looked up at Marco with wide eyes. Luffy might be difficult to raise, but he seemed so sweet. Even if he wasn't one of them, he'd still be loved and cared for. Marco was determined to do that. He'd tell him he had a quirk that made him look this way.

Maybe a "demon quirk" would work. He didn't know if Luffy would be upset by not being human, so he'd do his best to convince him he was. They didn't know how to and if they even could send him back to where he came from. So they'd help make him have a happy life, even in a world he didn't belong to.

-x-

"Ace! Sabo!" a four year old said, running to his brothers across the Whitebeard lobby. Thatch caught him around the middle and tossed him up.

"What did we say about the lobby?" Thatch asked. Luffy exclaimed that he said that he could run around as much as he wanted. "I'm not sure that's what we said. Try again." Luffy pouted and said he wasn't allowed to wander around the lobby.

Then he protested, "But I want to see Ace and Sabo." He whined that he was a big boy, too. Thatch humored him, that he was a big boy, even though he was still tiny, but that big boys also follow rules. "But… Ace and Sabo."

"Remember the walkie talkie?" Thatch reminded him. He unclipped the device from Luffy's pants. Luffy's eyes widened and he exclaimed that he'd forgotten about that. Thatch put him down and Luffy ran back into the kids' room, his feathers rustling as he did so. They were still too small to carry his weight. Which was good. He was enough of a trouble maker already, he didn't need to be able to fly off.

"Ace, Sabo, I want to play," Luffy said over the walkie talkie.

"We're doing homework right now, Lu. We can't play," Ace's voice said patiently on the other side. Luffy pouted deeply, but said, "Okay…" He was still pouting as he went to the ball pit and hid inside. In the dark, his body changed, his teeth getting sharper as his body elongated and warped so he was quadrupedal, covered in black fur.

He jumped out of the ball pit and immediately changed back. He liked his other form, he was so fluffy, but his family said he couldn't do it anywhere other than at home, even though lots of people had quirks that changed their appearances.

It didn't make sense to him, but he did his best to follow the rule since they were so serious about it. He went to the coloring books and started to color where he left off. He was kicking his feet behind him, laying on his stomach when he felt a strange sensation on his back. On his butt.

He turned around and saw something wiggling in his pants. He pulled them down a little and a black tail popped out, wiggling around. He screeched in excitement, and Haruta burst the door open, worried something had happened.

"Look! Look what I have!" the four year old said excitedly. Haruta's eyes widened, and Luffy ran in circles around the room excitedly. He was trying to burn off some excitement and tire himself out, and it worked. His tail was so cool, where did it come from?

Haruta tried to get him to stay still, and it worked when Luffy flopped into the ball pit. The hero seemed to not know what to do. So he went and got Marco, who walked in and Luffy jumped up and hugged around his legs. Thatch and Marco were his favorites. Besides grandpa Whitebeard.

Marco crouched and ruffled his hair, Luffy's wings rustling in happiness. "What happened there, Luffy?" Luffy said he was coloring when a tail came out of his butt. Marco asked him to turn around and look at the tufty tail, with a thicker tuft at the very tip. He bit his lip, and Luffy turned around to ask if it was bad, holding his new appendage in his hands.

"There's nothing bad about it. Some people might find it strange, but it goes along with your quirk." Luffy nodded, saying his quirk was awesome. He liked his horns and wings. They were really cool. And his animal version was very cool, too. "Your quirk is very cool, indeed. Why don't you go back to coloring? And call us if anything else weird happens, okay?" The youngest nodded and hurried back to his coloring book, tail waving around excitedly.

-x-

"Is this okay?" Haruta asked once they left the room. Marco asked what he meant. "The markings are changing again, and now he's grown a tail." The blonde said Luffy was a pure soul and wouldn't hurt anybody. Haruta said he knew he'd never hurt anyone on purpose. "But we don't know anything about him or what he is."

"There's no way we can find out," Marco pointed out. Haruta knew that was the truth. "We just have to go along with it and play it by ear. I don't like doing that either, but Luffy is one of us and we'll take care of him."

Haruta quickly said he didn't mean anything bad by what he'd said. He was just worried something might happen by accident. "I understand your concerns. I do, but there's nothing we can do about this. We just have to keep making sure nobody finds out."

Thatch came over with cookies and asked what was wrong, noticing their demeanors. Haruta explained the situation, and Thatch saw no big deal. "What do we do about school? If he changes form anytime the lights go out, a simple situation could expose him." Marco frowned, knowing that was a legitimate worry.

Luffy was turning five soon, and kindergarten was approaching fast. They couldn't bring themselves to force him to never go to school. They were raising him as a human, and human children go to school. "I'm worried, too," Thatch confessed.

Marco said, "At least he could pass as someone with an odd quirk. If quirks didn't exist, he'd be seen as a monster. As long as the HPSC doesn't know about him, he will be fine. We just have to make sure he's in control."

The other two nodded. Thatch brought the cookies to Luffy and put some on a napkin for him. "Ah! Thank you!" Luffy screeched and stuffed the cookies in his mouth happily, giving that look that made Thatch's heart melt. With his scrunched eyes and bright smile, cheeks pink.

"You're very welcome," Thatch said with a grin. Luffy told him to look at his new tail, asking that "wasn't it cool?". "Very cool. Maybe you can pick things up with it. Like a monkey!" Luffy gasped and said he would try. He went to the toy area and managed to wrap his tail around a toy and pick it up, only for it to fall. "Keep practicing and it'll be awesome," the chef hero said encouragingly.

Luffy beamed and nodded.

-x-

Luffy picked up an action figure with his tail, easily lifting it and putting it in the toy pile. There were two other little girls in there, one older than the other, playing with the doll houses even if they were crying silently. Luffy tried to talk to them before, but they shunned him, saying they walked to be left alone. So he did as they wished, and was practicing with his tail.

His tongue was sticking out of his mouth as he worked, setting the toys down neatly in one pile. Then he wanted to try something new, and wrapped the new appendage around the table leg tightly before lifting it easily, like it weighed nothing. "Wow!" Luffy screamed, unable to help it. He set the table back down and called Ace and Sabo on the walkie talkie.

It was the day after he got his tail, and Ace and Sabo found it was incredibly ticklish, so they did it mercilessly. "What's up, Lu?" Sabo's voice asked. Luffy told him his tail was super strong and to come see. He said that Ace was taking a rest and so Sabo would come down. Luffy would show Ace later, apparently.

It didn't take long for Sabo to arrive. "Watch, watch," Luffy insisted as he went back to the table and wrapped his tail tightly around it and picked it up. "I'm a superhero!" Sabo looked surprised, and the two girls were watching in shock and intrigue, even if they tried to hide it. One had orange hair and the other had light purple. Sabo clapped for him, and Luffy asked if he could try on Sabo.

"Sure, why not? But be careful." Luffy swore he would be and wrapped his tail around Sabo's waist before picking him up. Sabo clapped for him again and was lowered. "That's very cool, Lu. Your quirk is so amazing!" Luffy clasped his hands shyly and thanked his big brother. "You hungry? Thatch made some tortilla chips."

"Yeah!" Thatch's power was that he could conjure food or turn anything into food, including people. He could change them back, though. He was good at detaining people, but mostly stayed to watch over the kids, even if he was a hero. Usually it was everyone else who went out on missions and patrols. He also loved to cook, his quirk probably influencing that a bit.

The Whitebeards had tons of strong members. Whitebeard went out on big missions, but not normal patrols. He also liked interacting with the children. Luffy especially. Since there hadn't been a baby there in decades.

Luffy and Sabo hurried out of the room, both of them holding hands, Luffy much shorter than the 14 year old. They entered the kitchen and found the chef making salsa as well. Luffy walked up to the sack of chips and ate one. "What are two little devils doing in my kitchen?" he asked.

Sabo laughed and Luffy gulped. Was Thatch mad? No, probably not. He was never angry. "Sabo said you make - made chips!" Luffy exclaimed. Thatch nodded, but said that usually they waited. "I was hungry, though."

"Hmmm, I guess that's a good reason for breaking the sacred rule. Well, it'll fill your bellies when you have some of my amazing salsa. And you can share with Nami and Nojiko while they wait to be picked up," Thatch said, and presented the bowl of homemade salsa.

He scooped some out in a smaller bowl for the kids and gave them a bowl of the tortilla chips, taking the rest of the lobby for those on break to snack on. The agency had a huge kitchen, the building tailor made for the Whitebeards. After all, the pro-hero had been in the business for over forty years. He was one of the early generations of hero work. He was highly respected by all of the other heroes, even if All Might was ahead of him one spot.

It didn't bother him. He didn't work as a hero to be the number one. He did it to help others and form a family along the way.

Luffy carried the bowl of chips but tripped and dropped the bowl, only for it to freeze in midair. Everyone around went quiet. They stayed immobile for a moment before clattering to the ground. "What happened?" Luffy wondered. Then he remembered he'd dropped them and started to get teary. Thatch was there, and refilled the bowl.

"There is plenty to replace, Luffy. No need to get upset," he said kindly. Sabo picked up the spilled chips and threw them in the trash, continuing their way to the play room to share the food with the sad girls. Luffy didn't know why they were so sad, but he felt bad for them. They were crying a lot.

They did come over and eat some of the chips silently. Luffy and Sabo didn't talk to them, and instead talked about Sabo's school. He was going to UA in a couple months once summer break was over. He was excited. Luffy was excited for kindergarten as well. To make new friends. Sabo smiled awkwardly, but his little brother didn't catch on.

Later, after Nami and Nojiko were picked up by Robin, one of the foster mothers who worked with the Whitebeards often, Luffy was wondering what happened with the frozen chips. That wasn't Sabo's quirk. But Luffy already had his quirk, so he was a bit confused. But he wanted to try, since having more than one quirk would be awesome!

He threw a ball up and put his hands up, trying to stop it. He imagined the ball staying in the air, only that didn't work, the ball shot forward and bounced off of the wall and back into the ball pit. But something happened! Amazing! He attempted again and again until he was tired and wanted a nap.

He went to the napping area and flopped onto the couch, dozing until he woke up to the smell of dinner. The boy got off of the couch, rubbing his eyes and yawning before Thatch came in with his brothers, bringing dinner.

He ran to the kids table and started eating, Ace and Sabo with them, Marco joining later. "Hey, hey, I could make a ball go away," Luffy said around his pasta. Sabo reminded him of his manners, and Luffy swallowed his food before talking again. "It was cool!"

The other three didn't know what he was talking about, so Ace asked the four year old pleasantly. Luffy decided to show them, and ran to the ball pit, throwing it up and then making it go to the wall and bounce off. He wanted to impress them more, so he scrunched up his eyes and lifted a bunch of the balls a few inches up. Then he was panting from the exertion.

"That's cool, right?" Ace and Sabo were smiling, saying it was very cool. "But… I thought nobody had more than one quirk? Am I special?" Luffy hoped he was special. Marco said he was very special. Luffy beamed and shyly thanked him.

After dinner, Luffy went upstairs to their home to watch a movie. Ace went up with him, sitting on the floor in front of the TV, pulling Luffy into his lap, mindful of the small wings and new tail. They watched the animated movie happily, Luffy eventually falling asleep in Ace's lap. Luffy changed into his fluffy form, and the big brother turned the movie off and brought the little non-human to bed.

The fluffy Luffy was tucked under the blankets, Ace putting the stuffed creature that had come with Luffy next to him. He wrapped his small and sharp fingers around the doll and pulled it close with a snuffing sound. Ace smiled and closed the door behind him.

-x-

"You have to let him go to school. He has to learn about how to interact with people before elementary school starts, Marco," Sabo said quietly in the living room that night. Marco sighed, knowing Sabo was right. "I know - we know that you're just worried he'll be exposed. Just say his quirk changed his appearance and gave him that extra power."

Marco was frowning, hunched over. "I want him to live a normal life. Like a normal little kid." Ace honestly said that might not happen, but they had to try. Caging him would not be good for him. Ace and Sabo went to school, and Luffy was already excited about starting.

"You can't steal that hope away from him, and you know that," Ace said. Marco nodded, saying he knew that. He just wanted Luffy to be happy. Happy and feeling normal. "We all do. But that will not happen unless we do everything to make him happy."

Sabo was nodding in agreement. It was late at night, and Luffy was still sound asleep. "I think he'll get stronger. His tail lifted up a whole table," Marco said. "I don't want him to lose control. Or gain more powers that he can't manage on his own. Who knows what will happen next? He's not human, we have no idea what'll happen next."

Ace leaned into the couch. "We can't live in worry, sheltering him for his whole life. If he messes up… well, we'll deal with it if that happens." Sabo nodded in agreement. Marco asked when they got so mature. "We live with heroes. Of course we'd be responsible." The eldest grinned and closed his eyes in defeat, but not in sadness.

"I'll enroll him tomorrow. But we have to tell him what he has to do. To not transform into his other form in front of others. We can't do anything about his appearance, and we shouldn't have to." Sabo nodded. It was bad enough he had to hide what he was, even if he didn't have a clue, but trying to hide his appearance would be wrong.

He was fine the way he was. He didn't need to hide what he looked like. Luffy was Luffy, horns, wings, tail and all. At least he had a normal face. Big brown eyes and perfectly normal little teeth.

-x-

Luffy tossed the ball to Sabo, who tossed it back, Luffy stopping it in midair before forcing it back. He cheered, and the two continued practice in the week before the three of them started school. Luffy turned five the other day, so he was good to go to kindergarten that year.

He picked out a dinosaur backpack and new clothes himself, going out shopping with Thatch on his day off with no kids in the agency. They bought all sorts of clothes, mostly shirts and shorts. And new shoes that he loved. The lit up when he stomped hard enough. They edited the shirts so they could go around his wings.

People looked at him for just a moment before going back to shopping. Nobody looked at him too long, even if he looked different. Well, a mix of different traits. Luffy loved his new tail and wrapped it around things for fun.

Once Luffy got tired of playing with the ball, he and Sabo played tag around the room, Ace taking a nap. When Sabo caught him easily, he put him up high, holding him under the arms. "You're gonna be such a good kindergartener. I can tell already!"

Luffy beamed and said he'd do his best to be smart. "I'm sure you will absolutely do your best. We're all rooting for you!" Luffy said he was happy for Ace and Sabo for getting into UA. That they'll be so cool. Sabo grinned and tickled him, making his screech, his tail whipping around. It whipped too hard and hit Sabo's arm.

He winced, and Luffy noticed, seeing the tears of pain at his hurt arm. He dropped Luffy down, though he wasn't too high. "Sabo? Are you okay?" Luffy asked in worry, browns pulled together, afraid he'd hurt his brother.

"'M okay," Sabo said in a strained voice. "I gotta go tell Marco something." But Luffy knew his brother was hurt, and he wanted to help. He ran up to him and said he'd make it better. "Lu, it's okay. I'll be fine. Marco can fix it up."

Luffy wanted to help, but he had no healing power. So Sabo went to Marco, and then returned shortly after. "See? I'm all better." The swelling was gone, like it'd never been there. The smallest still felt terrible about hurting him. He'd be much more careful with his tail from now on. He didn't know it was that strong. Like, super strong! Too strong, so he'd be very careful to not hurt anybody else.

"I promise I'll be more careful," Luffy said with some sniffled of guilt.

The blonde put his hand on Luffy's head. "I'm not angry. Marco healed it. It was never going to be staying like that." Luffy nodded, sniffling, feeling terrible for hurting his brother. Sabo crouched down and hugged his baby brother, rubbing his back underneath his wings.

After a bit, Luffy calmed down and they got some food from the pantry and then went upstairs to play a game. Luffy still felt bad, but Sabo wasn't angry. Ace came out, still in his pajamas. It was 1:30. "Dang it. Stupid narcolepsy," he grumbled, rubbing his eyes. "What you two doing up here?"

Luffy said he was sad so they were playing games. Ace frowned and asked what he was sad about. Sabo stepped in and said it was nothing big, so to not talk about it. He sent Ace a look and the older brother nodded. They weren't brothers by blood, but had grown up together and called themselves that. And Luffy definitely wasn't their sibling by blood.

But, like the Whitebeards knew, family doesn't need to be blood related. They were brothers, no matter if they came from different places. Brothers, forever. And they would do everything to make each other happy.


My favorite way to start out many of my crossovers is baby Luffy! The fluff to start, and then the drama and action to come.