Yūki Saibai

Saibai is the father of Rito Yuuki and Mikan Yuuki, and the husband of Ringo Yuuki. He is a mangaka and is very different compared to Rito in terms of both looks and personality. Saibai draws at amazing speeds and can be utterly serious before deadlines are met, but seems to have a bit of a goofy side, such as making a joke about Rito and Lala "sleeping" together every night and punching Rito when he got drunk and mistook his son for a burglar. Like Mikan, he is casual, even amused, with his son's relationship with an alien girl, something Rito finds perplexing about his family.

Currently, Zastin and his subordinates work under Saibai as his assistants. With the help of Lala, Saibai returns for the Christmas party, stating how much Zastin and his workers have grown since starting out. In the anime, he writes a (not-so-encouraging) letter to him at the end of the first season.