Yousuke Koiwai

Yousuke Koiwai (小岩井 葉介 Koiwai Yōsuke), or "Dad" (とうちゃん tō-chan), is Yotsuba's adoptive father. The circumstances of her adoption are obscure—Koiwai tells Fuuka that without intending to, he found himself taking care of Yotsuba while somewhere overseas, but gives no other details. Yousuke grew up...