Based on the hentai comic carnage queen where Mary Jane Watson is taken over by the carnage symbiote.

Tragic villain seeking redemption and love

Dark Sakura is Sakura Matou, who was infected by the corrupted holy grail with Avenger's contract and feeds on its limitless power, she used be a sweet and sympathetic girl, but now has become an extremely domineering, powerful, and possessive girl with violent tendencies as well as slight hints of madness.