Often called "Killer" of "Killer Acid", Ryūichi Sasaki is an assassin who lives in the Tama district of Tokyo. Not a lot is known about his childhood, exept he lived with his parents and that his killer instincts were formed when he was young. He went to high school and had 2 years of technical school were he learned to kill.

He loves small animals, which is also his biggest weakness. He gun of choice is teh Beretta M92.

(Loosely adapted from the Japanese Wikipedia).