Havoc

A Regressor who lost her powers and a significant portion of her memories after Heaven's Gate disappeared in South America, five years prior to the story's setting. She used to be one of the worst and most feared Contractors, rumored to have killed over 100,000 people during the South American War. Her former powers are unknown, but are said to be similar to creating a vacuum. Her remuneration was to drink the blood of children

(From Wikipedia)