Kawamori began as a mall security officer in a building destroyed during the Great Kanto Hellquake, which created the underground settlement Evil Town. He rose to leadership in survivor faction Section A. Facing harsh conditions early on, he joined other men in raping female survivors, including future Section C members, establishing a pattern of sexual violence. As Section A's leader, he enforced brutal order, confronting survivor Kurata over stolen food. In the manga, he let Kurata die in Section B territory as a warning and eliminated associate Kinichi. The anime omits Kinichi but heightens his ruthlessness, showing him executing an unarmed girl for stealing ham and later murdering allies Sudo and Takamatsu to silence dissent or witnesses.

Kawamori eventually betrayed Section A by aligning with warlord Mad Saulus. The manga depicts his death when Mad Saulus crushed him. The anime expands his treachery: after joining Saulus, he lured Section C's Rikki into an ambush where Section B killed her. He then participated in the gang rape of Aila Mu (Aira), during which survivor Blue stabbed him to death in retribution. Across both versions, his character consistently displays cowardice, self-preservation, and a propensity for sexual violence, with the anime amplifying his villainy through added acts like child murder, killing former allies, and direct involvement in multiple sexual assaults.