Wielder of the Red Knife (OVA)

Set two years after the Red Hole incident and eight years before the start of the series, Senji Kiyomasa is a police officer using his Branch of Sin to fight criminals, but has a little temper. One day, he rescues a boy named Izuru who stole from a gang called Goreless Peace. After returning him to an orphanage, Senji encounters Goreless Peace's chairman, Keigo Ugachi, who also possesses a Branch of Sin. When Senji refuses to join him, he burns down the orphanage and kills everyone in it, including Izuru and the caretaker.