Rei Batsubami  

, ×喰零

The character you're referring to is a unique creation in the second season of anime. In this series, she was first presented as an ex-member of the Momobami family and Terano Totobami's guide and butler during their fight against Kirari Momobami. Although her motivations have not been disclosed yet, other members of the clan believe that she plans to seek revenge on him due to the Batsubami Clan's separation from the Momobami family.