Disclaimer: I do not own anything.

This is what happens when two of the shows I like the most runs in my head all day. Seeing a crossover fanart didn't help. The idea just bloomed on its own and demanded to be written down.

Inspired by Toffezel's fanart on Tumblr.

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It had been three days since Cora-san's death. Three days of Law trying but failing to live on his own in a big city with no one to fully rely on. He was an orphan, he has no friends. He only had Cora-san in a span of two years and six months.

Law did not even know why Cora-san had to die. He did not know why Doflamingo had to kill him. All Law knew was that one day when he got home, excited to tell Cora-san that he would go to the institute he went to and study there, the sight of his golden-haired savior lying in his own pool of blood met him. Cora-san's body was riddled with bullets but there was a kind smile on his face, he looked like he didn't feel pain at all. There was another person in the living room, the man's hair exactly the same color and shade as Cora-san's.

Doflamingo Donquixote.

Cora-san's older brother, his remaining blood relative, Law found out that fateful day. And he was killed by his own flesh and blood.

Law will never forget the man's wide, sadistic smile. He will never understand why Doflamingo killed his very own younger brother. The child knew nothing about Cora-san's past except the latter's desire to stop and eventually help an older brother whose path went astray, for all Cora-san focused on sharing with Law was the present and a wonderful future he promised the boy. Law felt angry with himself for not asking. Maybe he would know, if not understand, the reason why he was killed.

If only he asked.

He remembered Cora-san once told him that if was a funny word. To Law, it was a word that denoted regret for not making a proper choice; for not standing up to what he believed was right.

If only he asked Cora-san his past.

Law got out of bed and walked towards Cora-san's study table. Papers and books were stacked haphazardly on top of another and ink blots, both old and new, stained the dark hardwood. A picture frame sat on the clearest spot on the table and Law felt tears pricked his tired, grey eyes again.

He would only see Cora-san's warm, bright, and kind smile on photographs.

+.+

Cora-san's last will and testament stated that should anything happen to him, Law would inherit everything he owned. Now, the child lived all alone in a nice house devoid of happiness after Cora-san's death. He was left with money Cora-san generously spent on him but still felt he did not deserve it.

And inside the room Law was currently standing in, Cora-san's room, sat a strange-looking metal contraption in a corner. Law had no idea what was inside it, and it was one of the many tangible things Cora-san left him. The child had no idea what the thing was, how to open it, and what it could possibly contain.

With Cora-san dead, Law had no idea where to start again.

In fact, Law had no idea if he could start again at all. He had dealt with losses in the past, but losing Cora-san, the only one who took him in when the rest of the world shunned and ostracized him for his strange illness, was the hardest and the most painful of them all.

+.+

Law remained shut in the house in the fifth day after Cora-san's burial, ignoring his neighbors who tried to make him go out. They expressed their want to help him, but Law understood that it would remain as such. Want, and not need. Possibly even a make-believe that they wanted to help him.

Of all the people he knew in his short life, only Cora-san expressed the need to help him. At first Law thought that it was only a farce, but he learned soon enough that the need was utterly genuine.

He learned by experience that Cora-san was an utterly kind person. Clumsy and dorky, and too damn kind for his own good. Good God, Cora-san was altruistic.

At the end of the day, his thought always led him to Cora-san.

Law tinkered with the old pocket watch he last saw Cora-san worked with. The blond mentioned in passing that it was a family heirloom that stopped working at once when his clumsiness acted up in the park and caused him to take an unnecessary dip in the giant fountain. Law hit Cora-san on the head then when he came home dripping wet.

A small, triumphant smile appeared on Law's pale, thin lips when the watch started ticking, a clear sign that he made it work again. It was the first time he smiled in days, despite it being a little one. He became very good with machines and stuff ever since Cora-san took him in. The blond taught him after all.

"Hey, Cora-san, I- !"

He stopped midway in his words when he remembered that the man he was calling would never answer him ever again.

The brass pocket watch slipped from his grasp, dropped on the floor with a dull thud, and rolled a few feet away from him. Something warm trailed down his cheeks. Law furiously wiped it away and refused to acknowledge that he was, in fact, crying again. He walked towards the watch but on his third step, he tripped on his sneakers' shoelaces and fell flat on his face. A cry of shock and pain escaped his lips when he hit the floor.

Cora-san always tripped on his own feet and shoelaces when he was still alive.

Cora-san was so clumsy.

He was a huge dork.

He always caught himself on fire whenever he cooked and sometimes when he was inventing something.

He acted like a stupid guy despite his intelligence.

He was so kind, always prioritizing the wellbeing of another.

He was Law's savior.

He loved Law like a little brother. He was Law's overprotective big brother with self-confidence issues.

Law loved him, too.

With a loud sob, Law let himself crumble and cry.

Cora-san was dead. He was never coming back. And Law was left alone all over again.

+.+

Law was back in Cora-san's room on the seventh day after the blond's death. He was sitting on the king-sized bed, a picture of him and Cora-san clutched in his pale hands. The picture was taken last spring, Cora-san's most favorite season, when the cherry blossoms were in full bloom.

They were so happy that day when the picture was taken. They had taken out one of Cora-san's inventions for a flight test. The little machine was impeccable like the blond's other inventions.

Law then remembered why he was inside Cora-san's room again. Grey eyes took a look around as he heaved a deep, steadying breath, his eyes lingering on the strange metal contraption for a moment. He still hadn't touched nor attempted to open it.

"Doflamingo was finally caught by the authorities with the help of some weird, superhero-looking guys yesterday, Cora-san," Law started softly. He gently traced Cora-san's smile with trembling fingers. "It's great, isn't it? Justice will be brought upon him now, and he's finally been stopped from whatever he was doing, just like you wanted. But still, it… i-it won't bring you back…"

A single drop of tear fell on the surface of the picture frame. Law's vision blurred as thick, pearly tears clouded his eyes, his grip on the picture tightening.

"It's pointless, it is! Having him caught won't bring you back, and I hate it! I'm so tired of losing everyone I love, Cora-san! Why… W-Why is the world so unfair? This isn't what you promised me, Cora-san… I don't want to be alone anymore!"

The sound of some heavy metal lid being moved aside caught his ears and caused Law to look up, just in time to see the metal contraption in the corner or Cora-san's room to open up. The child watched, surprised, as something large, white, and printed with hearts (large, surrounded by smaller ones) sprang forth from within the container. Six feet and two inches, with Cora-san's favorite chullo with the heart tassels on its head, the thing opened its round black eyes and gave one blink before its gaze settled on the crying Law. There was a tattoo under its right eye. Its body seemed to be made up of some kind of a soft, inflatable material. On its chest was a badge-shaped cartridge.

Law watched as the thing walked towards him, taking awkward steps, before it slipped on the floor and landed on its back. The thing stood back up, clutching its head that resembled a Japanese bell. It took another step and clumsily tripped on the floor again.

The thing strongly reminded him of Cora-san. Did he make it?

Once it was back on its stump-like feet, the thing regarded Law with a benign look.

"Hello. I am Coramax, also known as Rocimax, but you may call me whatever you wish. I am your personalholy shit, Law, please don't cry!"

Before Law could react, he found himself wrapped in a fluffy embrace, the thing that introduced itself as Coramax, aka Rocimax, patting his fur-hatted head just like what Cora-san used to do. And to think that this thing was invented by the blond…

Law sobbed and returned the invention's hug without meaning to.

"It's alright to cry. Crying is a natural response to pain. Did someone hurt you? I'm gonna kick their butts! Please don't cry anymore!"

+.+

Law soon found out that Coramax he decided to call the bot was indeed one of Cora-san's inventions, co-created with someone named T. Hamada. A built-in video within the robot told him that Cora-san brought forth Coramax into creation with the sole purpose of letting Law know that he was never alone. Cora-san made the robot's memory chip contain the blond's traits and personality, as well as the clumsiness (Law thought that it must have been added to make him smile and laugh). Coramax was at his side when a kind doctor came and healed Law's illness. He never left Law's side throughout the ordeal, a thing the child was sure Cora-san would do.

There was a letter attached on Coramax's container, something Law overlooked a few hours after the robot made its existence known. There were dried tear stains on the paper and once he was finished reading and rereading the letter, Law clutched it close to his chest and cried. Coramax wrapped his squishy arms around the child and cuddled the latter close.

Law,

This guy right here is most probably my greatest invention ever. Actually, I co-created him with a friend, his name's Tadashi. He's a kind guy, wears a cap with the SFIT logo almost all the time. When I say almost, I mean it.

Anyways, back to the invention.

This idea about a healthcare robot originally came from Tadashi. Healthcare - see? He wants to help people, that's why Baymax was created. Damn, I got sidetracked again. Baymax is Tadashi's and I'm not writing this to discuss Baymax. This letter's about the other robot Tadashi helped me create.

Coramax (or Rocimax, whatever you want to call him) is a healthcare robot just like his brother Baymax. But Coramax's main purpose is not into doing stuff like what Baymax does. You can also see that his appearance is different from Tadashi's original design, I wanted my personal touch on this baby of mine so you'll remember me every time you look at my Coramax.

I know I can't always be with you, that's why I asked Tadashi to help me build a bot just like Baymax. I made Coramax's cartridge myself. Patterned his personality with mine, even, because Law, I'm scared. I'm scared that when I leave you, you'll forget me. I don't want that to happen. The thought of you forgetting me really scares me, Law. Because if truth be told, taking you in with me's the only right thing in all I've done.

I can feel that my time with you's already numbered. No, I'm not sick. My past is already coming up on me. I'm sorry if I can't talk to you about it, I just don't want to burden you with things that might bring you harm if you found out about them. I want to protect you, Law. I don't and would never want you to get hurt.

Coramax will always be with you when I can't anymore, Law. He'll take good care of you, hopefully just like what I did. I hope that I did good enough in taking care of you.

When I'm gone, I hope you won't forget me, Law. I hope that with the help of Coramax, you'll always remember me. And if you ever think of me in the future, Law, I want you to remember me smiling.

I love you, Law.

Your big brother, Rocinante Donquixote.

+.+

At the age of twenty-four, Law was now an accomplished surgeon. He found friends that cherished him just like Cora-san did. He never forgot Cora-san after all those years, and he was very grateful that the man he called his savior came to his life and then a robot that behaved exactly like him when he passed away. Cora-san never left him.

Cora-san kept his word.

The edges of Law's thin lips pulled up in a smile as he placed yet another piece of tape on Coramax's soft exterior. The robot slipped, fell down the stairs, and accidentally prodded Shachi's potted cactus with his fluffy arm. Coramax tilted his head to the side when Law started to chuckle.

"You're just as clumsy as the maker of your internal memory, Coramax," the raven-haired male told the robot, his smile turning into a teasing smirk. He chuckled again and shook his head when Coramax let out a whine that was very much like Cora-san's.

"You are mean, Law," the robot stated in a defeated manner. That made Law laugh.

"Watch your step next time, alright?"

"Please ask Shachi to keep that potted cactus away or else I'll throw it away."

Shachi, one of Law's best friends, who was on the other side of the room heard. "Oi! Not my cactus!" the red-head hollered.

Man and robot made their way to the living room where another of Law's best mates was at. A man wearing a cap with yellow visor looked at Law with a grin.

"The Big Hero 6 saved the day again, Law!" said Penguin cheerfully.

Law smiled and nudged Coramax. "Looks like your brother outshone you again, Coramax."

The robot locked Law's head in one of his puffy arms and kneaded a soft fist on top of a raven head. Law let out a surprised yelp, followed by a laugh after hearing the robot's response.

"I'm not made to be a hero. Besides, I'm here for you. That's what Corazon wanted."