My-HiME Episode 11: Dance of Light and Darkness
Episode 11 of 26 of My-HiME, aired December 8, 2004, 24 minutes. Available with English subtitles and dub where released.
Episode summary
A vampire is stalking the campus. It removes girls' clothing and drinks their blood trying to determine if they are HiMEs. Nagi tells Mai not to get involved with it, since there appears to be another group looking to use the HiME. The school's nun, Yukariko Sanada, turns out to be a HiME and defeats it.