Shikazo (Shikazo) was a distant relative of Tsukado that Kageki accidentally killed.
Konoha History Arc
Kageki had loaned money to him but when he needed the money for his family, he asked Shikazo if he can be repaid but Shikazo refused. A scuffle broke out and Shikazo fell and hit his head hard on a pickling stone, resulting in his death. Kageki's twin brother, Katazu, took blame for his death since then, attracting Shikazo's pursuers while Kageki and his family went into hiding. The one chosen with the task of avenging him was Tsukado. To do that he must kill Katazu, the man responsible for the death of his relative.