Chapter 9 of the Jigokuraku manga.
Summary[]
After infiltrating and rising up to the ranks of the Yamada Clan, Tōma manages to find his brother Aza Chōbei in prison and presents him the mission given by the shogun. Tōma then remembers their tragic life and how he learned that adaptation is key to survival. During the present day, Tōma and Chōbei encounter monsters on the island. Chōbei decides to slaughter them but sees that there are too many to fight and decides that they should run. As they try to escape, Tōma is caught by one of the monsters and asks for help from his brother. However, Chōbei continues to run off. Tōma then decides to fend for himself but Chōbei returns with a large axe and kills the monster attacking Tōma. Chōbei is then struck by another monster and hears it talk along with the other monsters. Tōma becomes worried but Chōbei becomes enraged by their speaking of sin and slaughters them. After Tōma admires Chōbei's ability to adapt, Chōbei states that he will kill all of the monsters and criminals on the island and claim the elixir for themselves.