Micasa

Severin's blood warrior. A silent young girl with long black hair. She was killed in the past by Severin and revived to be his blood warrior. She seems to have a complex relationship with Severin. She is a human blood warrior like Hiro, but is enhanced by a parasitic bio-weapon implanted in her head that gives her heightened combat abilities and Witchblade like powers.

[Spoiler] Micasa is a subject of the Fly Man, joining him in order to save her terminally ill younger sister. At the Fly Man's suggestion she later becomes Sylvia's blood warrior. [/Spoiler]

(Source: Wikipedia)