Suzuho Hasegawa

Described as being "Really shy. Takuto's sister-like-cousin. Boobs + Glasses" She is Takuto's cousin and is so shy that she is mute, communicating to others by writing on a sketch pad and hiding in various objects, the most common is a doll helmet which the eyes also move on their own. She too is a magic user like her cousin but she has a rare ability to suck the powers of any magic user around her when she unbraids her hair, turning a distinctive blue color which earned her the nickname from her terrified fellow classmates "Midnight Blue Vampire." But in this form she speaks rudely and has no strength other than a normal teenage girl, leading her to use a mechanical sword called Warcurgis which with no magical properties isn't affected by her powers. It has been confirmed that she is another personality of Suzuho, she referred to Takuto as "ours", and her blue haired personality was referred to as the other Suzuho. She also seems to have the unique power of bringing Takuto back to life where she grabs his spirit and thrusts it back into his body, but this could merely be something focused on for comic relief. She clearly has affection for Takuto, blushing to his compliments and nearly destroying Magic Academy to get him back; because of this she moved in with Takuto now that he lives with Tanarotte to keep an eye on her. However anytime a character points that affection out, she gets extremely nervous. In episode 4 she becomes a student in the same school as Takuto where she is popular among the other female students because of the high-class high school she used to go to before this school.

Source: Wikipedia