These are all headcanons honestly but i wanted to put things together
Kokichi was a shy and timid, small child. He never had the advantage of height and was always deemed shorter than his peers. Due to those factors, he gained many bullies at the school he went to. Not only was his body more petite in comparison to everyone else's, but kokochi also lacked the confidence and social skills to tell anyone, making him the prime target.
Yet at home, Kokochi knew how to act perfectly fine. He put on a mask of happiness and childishness at home, and knew how to control himself and his expressions.
Kokichi had always lied about everything at school being well. His parents favored his older brother very much, from the way he had amazing grades, to the way his appearance was careful manners torwards everyone. His parents held many expectations of his brother, and needless to say, the two siblings were nothing alike. Bad grades, a sloppy appearance, kokichi was the opposite of his brother.
His brother was the perfect child. Kokichi was the dissapointment.
Yet kokichi hand never minded that fact, because despite everything, he and his brother's relationship had remained close, and he held a deep admiration for his older sibling. He didn't want to cause anyone troubke by mentioning the bullying at school, so he lied about his bullies to everyone.
His brother was always studying for his grades at home whenever he could, sometimes under the order of his parents. Yet not once had kokichi seen his brother unhappy about his situation, or show any signs of disobedience torwards his parents. His mannerism alwys remained completely composed. He had little free time, but kokichi always treasured every last moment they spent together while his brother was free. He could act as himself with his brother, and they knew each other the best.
Sometimes when having nightmares, he would sneak in his brother's room and snuggle with him under his blanket. His brother locked the room, knowing kokichi had the ability to pick locks. Both of them never told their parents about their midnight talks. His brother was one of his only sources of comfort.
In his scarce free time, kokichi would notice that his brother disapears from the house for a few hours. This dissapearance became more frequent, and the hours spent took longer. Kokichi decided that he would follow his brother next time, out of curiosity of what he was up to.
The revelation hit kokochi like a truck. His brother was secretly in a small gang that was pretty well known in the area as "DICE". The gang consists of several orphans and were extremely strict in that manner. His brother was one of them. kokochi watched them converse, using slangs and swear words. He watched as his brother gulped down alchohol and laughed at vulgar jokes. He was using a fake name, and lying about being a single child orphan like the rest them.
So this was his brother. Well, it was only natural that someone with so much pressure would be seeking escape from their harsh reality.
Yet kokichi could not help but feel a sense of dissapointemnt in his chest. His admiration for his brother wlowly dissapated as he watched his brother's other personality.
This was the part of his brother that he hid from kokichi underneath the facade of etiquette. This was the truth underneath his brother's lies. Kokichi wished he had not discovered the truth, that he could have led to believe his charming and perfect older brother, his model, his inspiration.
He knew that it had all changed. He couldnt hold on to his beliefs anymore, and knew he had to face the cold, harsh reality of his brother.
It was ironic. His brother was lying to everyone about his personality to keep his life, while kokichi was lying about his life to keep his personality. Although brothers, they were so similar despite their many differences. Well, they were siblings afterall.
Kokichi was so fixated on his brother that he had not notice one of the other members creeping up from behind. The member pulled on kokochi's hair unsuspectingly, and dragged kokichi to the gang as kokichi tried to pull free frpm that member's grasp futilely.
As kokichi was brought in closer, his pale, purple hued eyes met his brother's, and both of their eyes exchanged several anxious messages within that wuick glance. His brother' expression was equivalent to a shocked, horrified expression, while kokichi was sure that he could not help but portray a terrified, anxious one. But another member broke that contact between them before they had the chance to exchange words.
"Wow, whos this little guy?" She jeered at him.
This felt exactky like it had in school. Where everyone taller had picked on him because of his small frame. He felt like a small, powerless sheep in the territory of lions. Kokichi was, of course, terrified. Yet he could not let that fear show on his face. Not now.
He was best at controlling his emotions, afterall. It was one of the only things kokichi could do right. He calmed his nerves as he put on yet another performance.
"Kokichi Ouma's my name! And if you couldnt tell, I'm his brother."
The brother he was too ashamed to be honest about.
His brother always expressed to kokichi that he was proud of him no matter what, and would always be with him, even if their parents werent. He had always told kokichi that he would never be ashamed of him, and that he wasnt a dissapointment. His brother called kokichi his pride and joy, which kokichi still remember and held onto until today,
Well that was obviously a lie too.
Kokichi felt their gaze shift onto the person he was pointing to, who became increasingly horrified as they each turned their heads torwards him. His brother.
It was a taunt, directed torwards his brother. Kokichi's pent up emotions and anger torwards his brother led him to this action, before he realized the gravity of what he just did.
Kokichi felt the tension rise as the anger of the members were directed at his brother. And he was the cause of it.
Before he knew it, everything escalated faster than he could react. A fight broke out among the members and he watched his perfect brother get beaten as he had i school. Before he knew it, his fragile and beaten brother was in his arms, and kokichi was handed a gun by one of the members.
"Shoot him and you live."
Those words echoed through his head.
"Only you can get out of here alive. Do it."
He was in a gang. Notorious for their cruelty. That was what they were famous for.
Shakily, kokichi brought the gun to his brother's head.
What else was he supposed to do? They would never let his brother escape, and he would die if he didnt kill his brother.
Kokichi brought his fingers to the trigger. Is this it? He's going to murder his own brother right here at the moment, just to save himself.
No. Kokichi never wanted his outcome. If these were the consequences of his actions, kokichi would much rather bring himself to be the one punished for his own actions. "I-I can't-" kokichi started, before his brother Grabbed his hand with the trigger.
"You're still my pride and joy." His brother gave one last smile before pulling the trigger.
Pink blood splattered all over kokichi as he watched his brother's life fade right before him.
When kokichi arrived back home, it was past midnight. He caught the sight of his parents waiting in front of the doorway. Probably for his brother.
Well, they should be prepared to wait forever.
"WHERE IS HE?!" His mother grasped kokichi's sholder, squeezing it hard.
"ANSWER ME!! WHERE IS MY BABY BOY??"
Kokichi couldn't raise his head to face them. He couldn't stand to lie anymore. Not after everything that happened.
But what would his brother's death had been for, then?
His brother wasted his entire life, trying to be perfect. Trying to make their parents happy.
All that time spent for something so insignificant. His brother was reaching for the top when nothing was up there.
Hesitantly, kokichi brought his eyes up to face his parents. He saw their mortified faces. It was the truth that shocked them the most. The truth ended up harming them more than both pf their lies.
kokichi walked away from his parents after he revealed those words to them. He walked away from his home.
The gang was quite suprised to see kokichi show up there, after finally letting him off. And quite displeased at the fresh memories he brought them too. But it doesnt matter. Kokichi wanted revenge.
Kokichi said he had killed his parents to the gang, which was true. He killed their morality and life ashuman beings after he announced the sudden news. And he never intended on going back to their graves.
He challenged the leader of the gang to a competition of leadership. The knife game. He won the game and became the leader of the gang. The leader of devils. The leader of evil.
After his ruling, he orchestrated many harmless pranks, dialing down the cruelty. The gang became more known as fun jokesters instead. He learned the lives and personalities of each 9 members and they grew closer after their reluctant hatred torwards one another in the beginning, He earned all their trust, and they became the family he always wanted.