Atsuo was an anthropomorphic cat moneylender.
Atsuo's father was an ethical moneylender who was interested in helping his fellow citizens. Upon his death, his business was inherited by Atsuo. Atsuo had been a good-natured child, but his power changed him, and he became greedy and cruel, sending his thug Bunjuro to rough up those owing him money, mistreating his mother, and hiring a troupe of thugs to protect him.
Atsuo's mother, horrified at the change that had come over her beloved son, tricked Atsuo into believing that the ronin Miyamoto Usagi had been hired to kill him. When Atsuo sent his thugs to kill Usagi pre-emptively, Atsuo's mother murdered him, and then asked Usagi to assist her to commit suicide. Usagi, reluctantly, agreed.