The Chiesters are bunny-girl servants summoned by Beatrice. It is said that there is no escape from the Chiesters attacks, and they can even locate and bring back a corpse. They have red eyes, bunny ears, and elaborate military-styled outfits. It is hinted that they are connected to Maria's three (originally four) rabbit toys.

She is named after the "00 buck" shotgun load. Chiester 00 wears a black uniform and has long blonde hair. She has an eyepatch over her left eye, and her left bunny-ear has a scar. As the leader of the summoned Chiesters, She is very composed and serious in her work. She is in charge of guard and recon.