Muh headcanon

>Gaku was born to a rather poor household in Minasato
>Although not really social, he liked to play games at the arcade, and got along with other people just fine.
>Being a crossbreed, unlike main branch Kodori members, who tended to be short, Gaku was quite tall.
>His father was an abusive asshole who did not take to this much, and would scold him and at times beat him, blaming him for any misfortunes due to being a mutt and being unusually tall.
>He is trained to be a fighter. His fellow student is Ten, a relative and product of cross-breeding. Gaku doesn't want to be a fighter, because he didn't want to be like his dad.
>Thus, while Ten is well built to the point of looking like a superhero, Gaku ends up looking weak and lanky.
>At age 13, his mother dies after slipping on the stairs to the Minasato temple and breaking her neck, dad goes apeshit and blames it on Gaku, claiming he pushed her down, even though he was at his friend Mitsuhisa's house when it happened. Dad, pissed beats Gaku even worse than before.
>This experience makes him bitter and more fearful for his life.
>At age 15, it's determined that he is in line to become the heir of his branch of the Kodori family. In a ritual that was abolished long ago by the rest of the  main and branch family, he is gangraped by several members of his family, including his father, in the misguided belief that breaking the mind of the heir through physical and sexual abuse will make him more courageous.
>Already paranoid after the temple incident, this sends Gaku off the deep end. He becomes even more unhinged, and slips into depression.
>On his 17th birthday, he meets his cousin Ten, whom he asks for help running away. Ten seemingly declines, but slips something into his bag.
>He opens it and finds it's the "Kodori Guide to Sex"
>Gaku freaks the fuck out and asks how Ten got it and why does the family have a sex guide
>Ten is unable to give an answer, but tells him to end the Minasato Kodori sect's rape rituals using it. He doesn't tell how.
>Gaku slaps Ten in anger. Ten gets pissed and manhandles Gaku. Ten says that he's on his own now regarding the situation, but would still consider him a friend.
>After graduating high school, Gaku moves out of Minasato and cuts all contact from his family, save for Ten. He moves to Kazenari (or whatever it's called) and, with the help of a co-worker, opens up a game store. He manages to make a rather steady income despite the stress it causes him. He rarely eats much, just enough so that he doesn't starve to death, but not enough that he doesn't look like he's made of paper.
>Gaku calls Ten about what's happened since he moved out. Ten fucked up a dodge while training with real swords and got some nasty scars as a result. Mitsuhisa's family is wracked in financial hardship because he got laid off and had a dispute with his son Kouya. Ten tells him about the birth of his cousin, named Shun who is the new heir after Iwao, who took over after Gaku's grandfather died.
>Gaku wants Shun to live a life free from the hardships he had, and decides that he would protect Shun from anything that could cause him harm or environments where he cannot find happiness.
>Years later, it turns out Kouya has been hanging out with Shun for quite a while. In addition, Hiroyuki Nishimura, another friend of Shun and a son of one of the few humans he tolerated was staying in his hometown of Minasato for that summer
>He is worried about Kouya being with Shun
>And so it goes