Myoudouin Itsuki (明堂院 いつき Myoudouin Itsuki?) is the student council president at the Myoudou Academy Junior High School. She is the granddaughter of Myoudouin Gentarou, the president of Myoudou Academy. Because she looks and dresses like a male, she is often mistaken as one by new students, and even people who know about her situation state that sometimes they forget that she is a girl. She cross-dresses because she chose to take the place of her older brother, Satsuki, who is too sick to act as the heir of the family dojo. Her Heart Flower is the peony, symbolizing her rebirth as a person and her noble background. Itsuki's Cure ego is Cure Sunshine (キュアサンシャイン Kyua Sanshain?) and her catchphrase is "I will heal the darkness in your heart with my light!" (その心の闇、私の光で照らしてみせる! Sono kokoro no yami, watashi no hikari de tera shitemiseru!?).
Itsuki is gentle, civilized, and very caring for her friends. She is also shown to be somewhat girly, as she finds many toys to be cute and has fashion desires, though she hid them at the beginning. Every time she see's Potpourri showing cuteness, she goes (insanely!) girly and forgets to be calm. Speaking of which, she is usually calmer than Tsubomi and Erika, but nevertheless dislikes seeing her friends suffering or in pain. Like Tsubomi, she has a more calm and caring personality; Erika's lively and carefree manner contrasts sharply with both of them. Itsuki appears to be a gentle, handsome, and athletic girl with a princely demeanor who attacked many subordinates and fans. At the beginning, Tsubomi developed a temporary admiration for Itsuki until discovering her female gender.