Koichi Adachi - Yakuza: Like a Dragon wiki
When Ichiban is released from prison, Adachi is there to meet him. Adachi wants Ichiban to help him with an investigation into the Tojo clan. The main thing that Adachi wants throughout the whole game is to find evidence that the police commisioner took bribes. His sole goal in life at this point is to expose the police commisioner for corruption.
The reason Adachi hates the police comissioner is because he kept an innocent man in jail in order to secure a promotion to police comissioner. The man in jail was falesly arrested by Adachi and inveitable commited suicide in prison. This has haunted Adachi ever since.
According to the game profiles:
"Former police officer. He was demoted to working at the driver's license center after he disobeyed his supervisor, Horinouchi, in the Criminal Investigation Department. Then, when he found out Horinouchi had been taking bribes from Masumi Arakawa, he was summarily dismissed on disciplinary charges. Now, with his future in law enforcement ruined, Adachi will stop at nothing to seek vengeance on Horinouchi."
Adachi's unique job is detective. He's usually a melee oriented playable character and can also perform the jobs of: Bodyguard, Foreman, Enforcer, Breaker, Musician, Host, Chef, and Fortuneteller.
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