Kanoe Yuuko from Dusk Maiden of Amnesia. (Shadow Yuuko included) [Spoiler!] Every evening there's a chance that she'll be possessed. Depends on her mood, there is a chance that she'll kill the one NPC she hates or PC (Yeah, you. No matter how she liked you or not). If she's player-controlled, there's a chance that player will lose ability to control her once she's being possessed. Player will regain her control once she receives hug/headpat from any NPC. [End of spoiler]