Decisive Battle at Kuoh Academy!.Sona and her team form a barrier surrounding the school to contain external damage while Rias and her team prepare for their battle against Kokabiel, Freed, and Valper. The battle begins with Kokabiel summoning several Cerberus demons to battle the Gremory Team, who are successful with the help of Xenovia. During that time, Valper successfully combines the four Excaliburs while triggering a self-destruct magic circle that will activate in 20 minutes as a stranger looks on from afar. Rias and Akeno then attempt to battle Kokabiel but prove useless against his powers. Meanwhile, Kiba confronts Valper and realizes the truth of the Holy Sword Project. With the help of his friends, Kiba successfully attains his Balance Breaker, and together with Xenovia who summons her Durandal they successfully destroy the Fused Excalibur. Kiba attempts to kill Valper but Kokabiel kills Valper first and reveals the Occult Research Club that Issei can transfer his power to anyone as Issei prepares to transfer his powers to Rias.