Saizou is Souji's pet piglet. Saizou is temperamental at times (mostly towards Tetsunosuke) and is often seen chasing and "attacking" Tetsu. However, Saizou adores Souji and seems to be nicer to those with a gentle nature (when compared to Tetsu) such as Yamanami, Ayumu, and Hotaru (the Choshu maiden who had a crush on Souji).