Jade Setsuna

Jade Setsuna is one of the four Lords of Death. Setsuna appears as a male human ten-year-old child wearing a blue robe and cape, with mop-like hair and long, sharp fingernails that he uses as weapons in battle. Cunning and manipulative, Setsuna targets his victims' weaknesses before he strikes. Despite his child-like appearance, he is the older brother of the hulking Rasetsu.

(Source: Wikipedia, edited)