Ikuko Tachibana

Ikuko Tachibana (橘 郁子 Tachibana Ikuko) is the wife of Keisuke Tachibana, the biological mother of Misuzu Kamio and the sister of Haruko Kamio. She is first mentioned in Episode 11 by Keisuke.

Trivia

 * The name Ikuko means "fragrance" (郁) (iku) and "child" (子) (ko).
 * Ikuko's surname Tachibana means "orange, tangerine" (橘).
 * Ikuko's former surname Kamio means "god" (神) (kami) and "tail" (尾) (o).
 * It is possible that Ikuko passed away in an accident or illness