Ravel Phenex

Raiser's sister. She is also Raiser's Bishop. She follows her brother's authority to a full degree, as she sees that there is no one who can defeat him. Just like her brother, Ravel is also a Phoenix. After seeing her brother's defeat at the hands of Issei, she becomes infatuated with him, and later transfers to his school so she can spend more time with him. Later on as the story continues, she falls in love with him completely, and does not mind becoming his concubine so long as she can be with him. She is currently a "free" Bishop since she traded herself back to her mother's team (who does not participate in Rating Games). It is likely she will trade herself to become one of Issei's Bishops when he gains peerage, as she wants to be of use to Issei. She moves into the Hyodo residence in Volume 10.

She becomes Issei's manager and manages his schedule and activities as the Oppai Dragon
In Volume 22 her mother trades her with one of Issei's bishop pieces, making her Issei's Bishop.