Owari no Seraph: Nagoya Kessen-hen

Yuuichirou Hyakuya has finally found Mikaela alive, only to learn that his childhood friend has become a vampire. Before he can find a way to save him, the Japanese Imperial Demon Army learns that vampire nobles are gathering in Nagoya, and Guren Ichinose leads several squads into an operation meant to strike them before they can attack Tokyo.

Shinoa's team trains to deepen its control over cursed weapons and improve its coordination, but the mission quickly exposes how little they understand about both the vampires and their own commanders. As Yuuichirou's demonic power grows harder to contain, loyalty to his squad and his promise to rescue Mika begin pulling him toward choices that could reshape the entire conflict.