He is the Hikyou (Cowardly) Banchou. His catch phase is "lets fight in a fair, cowardly way" He will use anything to win (lies, sneak attacks, covert weapons, kidnapping, etc) he attacks Akira with a seris of traps. Using a cell phone shaped pistol on a train to injury his leg, blowing up and office to temporally blinding him, tricking a semi-blind Akira to jump into traffic using a ball (lying to Akira saying it was a grenade) breaking his right arm, kidnapping Tsukimi so that when he finally fights Akira has to hold still. He was defeated when he tried to use a wrecking ball on Akira and was sent back at him. Akira was ready to deliver the final blow when Yuu's underling (Kouta on of his little brother) intervened stopping Akira, Harito appears and uses Kouta as shield telling Yuu to stab Akira. Yuu does so then fake stabs himself trying to save Kouta in the end Akira saved both of them since the knife had no effect on him. His reason for helping Akira is so that Akira will be indebted to help him when needed and he plans to back-stab Akira when he wins control over all the districts (the real reasons is most likely that he is thankful to Akira who worried about his (Yuu's) family even if he tried to kill him). He grew up in an orphanage where he has 13 little brothers and sisters (no blood relation) to support the orphanage (after the owners lost they money to gambling debts) he would do any dirty job for money (blackmail, fraud, stealing, etc) He wears a burglar mask and cap when he fights so others don't know what he looks like, so they don't set traps for him and also so his family won't be put in danger, he states "if it's for the sake of my precious brothers and sisters I'll be as cowardly as it takes".
Vova
