Adopted by Yurine Hanazono after being mistaken for a stray dog, Bête (also called Beth) is actually a Beast of Gévaudan, a species known for endangering humans. She lives outside Yurine's apartment as a domestic pet. Bête resembles a small, furry brown quadrupedal mammal with dark stripes and a distinctive mohawk along her back, traits aligning with the legendary Beast of Gévaudan, though Yurine sees only an ordinary dog.

She behaves like a house-trained dog, showing obedience and engaging in routine interactions, including interest in other female dogs. Defying her species' typical aggression, Bête has never attacked Yurine, highlighting their unique peaceful coexistence.

Her relationships with others are complex. Jashin-chan attempts affection but sometimes gets bitten, suffering minor injuries like hand amputations. Despite this, Jashin-chan persists, and Bête acts as a grounding influence, a "morality pet" mitigating Jashin-chan's volatile tendencies. They share mutual tolerance; Bête is one of the few characters Jashin-chan never yells at. Bête formed a significant bond with Minos after Minos moved to the human world. In Hokkaido, Bête served as Minos's shepherd dog, assisting her daily and showing loyalty beyond typical pet behavior.

Pino, the heavenborn apartment manager, supervises Bête and uniquely understands her growls and barks as human language, facilitating communication and oversight. Vampires instinctively fear Bête due to her species' predatory nature, revealing supernatural vulnerabilities.

Throughout all series media, Bête remains a supporting character. She contributes comedic and narrative elements through her interactions, serving as a stabilizing presence for Jashin-chan and a cooperative companion for Minos. Her background as a Beast of Gévaudan isn't expanded beyond her adoption; her development focuses on integration into the human world and her relationships.