She is Ratten's master. She appears as playful, yet is very loyal to Pest. She got jealous of Weser when Pest gave him divinity.
She is Weser's master. He serves her loyally and was given divinity before another duel with Izayoi.
He was given a ring to summon her as a comrade of the No Name. From that time on, she has been helping out with the daily activities as a maid. (Shiroyasha's personal maid costume collection set) Later on in the series, she is shown to grow closer to Jin.
She respects this monster-like human. Precisely because of his monster-like powers that are totally unexplainable and he kind of treats her like a smaller sister of his. Dragging her to the bath and threatening to bathe her personally if she doesn't get along with Asuka. She also joins in the fun with the problem children in Volume 7 where she takes part in his plans to convince the crowd through unconventional means. Like with his fist.
Other than practice sessions, they do not usually come into contact. She likes to tease others that she doesn't usually realize that she had passed the limit of their capacity and have felt hurt. As seen in Asuka's case and it is fortunate that the case was settled by the appearance of Izayoi who made it seem more of a gag comedy. But Percher prefers to tease Kudou Asuka whenever she has the opportunity.
A fellow maid that Pecher quarrels with on various occasions.
He was the one who held the books to summon her to this world. She knows nothing much about him other than the fact that he is the leader of Ouroboros and that the only person ever to damage him slightly is Izayoi.
Percher's main goal is to gain revenge on the sun, in other words, defeating Shiroyasha so she can reverse the events of the Black Plague.