Rei's twin brother, Sei, was a sensitive artist who tragically took his own life during their final year of junior high. Rei had always been taught to protect his brother, leading him to blame himself for Sei's death.
Towards the end of the series, Kira, and only Kira, discovers a shocking truth: Sei's suicide was primarily motivated by a desire to make Rei suffer. She uncovers a hidden suicide note in which Sei explains this motive.









