Yuuri Kumoi

Real Name: Juli (ユーリ)
Goes By: Kumoi Yuuri (雲居悠理)
Codename: Phantom Daughter (ファントム・ドーター)

Juli is the daughter of the head of Black Phantom. As a high-level hypnosis user, she brainwashes the organization's kidnapped espers in effort to receive her father's love. She initially has three personalities:

"Juli" - Referred to as "Mirage" (ミラージュ) by the other personalities. She is the true personality who appears with blonde hair. She appears to be starting to rebel against her father. While stoic and seemingly devoid of feelings most of the time, she is very protective of Nye, her bodyguard.

"Phantom" - A more sadistic personality with hot pink hair who houses the true intentions and feelings of Mirage. Mirage created Phantom as an outlet for her feelings due to not being able to express them in any way herself. She wants to 'play' with The Children forever, often causing trouble for them.

"Kumoi Yuuri" - A shy normal girl with dark hair who is unaware she's an alter ego. She was created by Mirage to disguise herself as a regular schoolgirl and get closer to The Children. Due to her growing feelings for Kaoru, she gradually gains a will of her own.

(Source: Wikipedia, heavily edited)