Seishu Inui/Synopsis

History
Seishu is the second born sibling in the Inui family, five years younger than his elder sister Akane Inui. He and his sister shared many key characteristics appearance wise and often spent time with her along with his childhood friend Hajime Kokonoi.

During a fire that tore down the Inui family's house Kokonoi ran into the house to rescue Akane but mistakenly comes out with Seishu, causing his sister to be more injured as she remained in the fire longer. His elder sister later passes away and among that his best friends sanity. Koko often thought of Seishu as Akane going as far as kissing him. They remained by each other's sides throughout their lives.

The founder of the Black Dragons Shinichiro took him in. Seishu sees the pure humble nature of Shin and the interactions between him and the gang and wishes to join. Looking up to him and wanting to be like him he started wearing high heels. By the time he was able to join the Black Dragons was taken over by Izana and Seishu his right hand man. During that time the gang committed many crimes and landed many of them in juvie. Seishu later despises Izana for ruining the dynamic of the gang Shin created. During the time Seishu was in reform school, Koko waited for him and informed him that the Black Dragons fell.

His goal became reviving the Black Dragons. Alongside Koko, they served as Black Dragon 10th Gen captains of their respected lanes serving under Taiju. Seishu believed Taiju could bring the Black Dragons to strength again.

Black Dragon Arc
After the fall of the Black Dragons, Koko and Seishu join Toman and fall under the leadership of Takemichi in the first division, combining the Black Dragons and Toman.

Tenjiku Arc
As the battle of the brothers and their respected gangs near, Koko, Takemichi and Seishu get kidnapped and held captive. They later released Seishu and Takemichi but at the cost of recruiting Koko to Tenjiku. Driven by his drive to save Koko, he turns to Takemichi for help, announcing he would die for Koko. Wanting Koko safe, wanting Takemichi to save them.

As he sees Shin in Takemichi. He offers him the Black Dragons making him the 11th Gen Leader.

During the fight against Tenjiku, Inupi was willing to kill to get Koko back. Koko offers Inupi a position at Tenjiku for them to be together again after Inupi told him to come back to him and Toman. He wants to protect Koko and has been trying their entire life. Seishu cries out to Koko that his sister is dead and he is not her. That he has no need to obsess about money anymore because Akane is long dead. Seishu was also unable to fight Koko as he meant too much to him.

Koko and Inupi ultimately go on seperate paths, wanting the best for each other. In an alternate present, he and Draken opened a bike shop together called D&D with their combined mechanic skills in Shinichiro's memory.