After Riser's defeat at the hands of Issei in Volume 2, Shirou won a previously set wager between them, granting Shirou half of Riser's servants as his own, thus giving Shirou the early opportunity to begin building his Peerage. So far, the only two revealed members are Isabela, Riser's former Rook, and Ravel Phenex, Riser's younger sister and former Bishop.