Shinobu Sensui

Shinobu Sensui is a character from YuYu Hakusho

History
Shinobu Sensui (仙水忍, Sensui Shinobu) also known as the Black Angel, was the main antagonist of the Chapter Black Saga, as well as a former Spirit Detective in his youth, having been recruited by Koenma for his prodigious talents and his unequaled sense of right and wrong. In the anime television series, Sensui is voiced by Rokurō Naya (adult) and Akira Ishida (teenager) in Japanese and Robert McCollum in English.

More Information: http://yuyuhakusho.wikia.com/wiki/Shinobu_Sensui