Akio

Akio is an old friend and former classmate of Kyohei, known for always standing up for him. After falling on hard times, Akio is discovered by Eiji, a Yakuza member who takes him in and has a doctor transform him into a Cyberoid. Consumed by vengeance, Akio wages a one-man war against the Yakuza. In response, Eiji, seeking favor with the Yakuza boss, strikes a deal to eliminate Akio. However, the plan backfires—Eiji’s betrayal enrages Akio, who guns him down. Before his final battle, Akio confides in Kyohei, revealing how he became a Cyberoid. After eliminating the Yakuza and their boss, Akio faces Eiji, who has also been turned into a Cyberoid. Though Akio emerges victorious, he succumbs to his wounds, leaving Kyohei devastated by the loss of his friend.

(Source: Wikipedia, edited)