Kohaku is a rather accidentprone angel who has come to Earth in search of their mentor Hisui but ends up trapped in a tree and attacked by a crow. Theyre rescued by Shuichirou a young doctor so they feel indebted to grant him one wish even if the kind doctor is satisfied with all aspects of his life. Thus Kohaku remains with Shuichirou in hopes of repaying him somehow subsequently getting in other sticky situations as a result. Wish spoilers Kobato spoilers In the anime series Kohaku is introduced early in the series and befriends Kobato. Because Ioryogi is aware of Kohakus true nature he constantly asks Kohaku if theres something they can do to change Kobatos wish though Kohakus response is always that theres nothing to do. At the end of the series it is Kohaku who explains to Fujimoto the nature of Kobatos wish and assures the young man that if they are fated to be together they will be in time./spoiler DrugampDrop spoilers Source: Wikipedia