Sairaorg Bael
Regulus Nemea (Longinus)
Sometime before the series, Sairaorg found Regulus, the Lion King, sealed in the Longinus, Regulus Nemea, after its possessor died and it materialized itself. Sairaorg then tamed Regulus and made it his servant through 7 Pawn Evil Pieces.
In Volume 10, Sairaorg faces Rias in their Rating Game, during which he eliminated Yuuto Kiba, Xenovia, and Rossweisse in the games, facing Issei in the final round. While initially refusing to use the Balance Breaker of his Longinus, Regulus Nemea, he eventually used it after persuasion from Issei. In his Balance Breaker form, Sairaorg’s strength and speed increased greatly to the point where he easily shattered Issei’s Scale Mail in Rook mode. Despite this, he ultimately lost to Issei after the latter manages to achieved his Cardinal Crimson Promotion in their battle, fighting Sairaorg in a fist fight which Sairaorg lost after losing consciousness.