終わりのセラフ

In a world decimated by an apocalyptic virus that turns humans into vampires, Yuichiro Hyakuya and his childhood friend Mikaela Hyakuya are among the few survivors, living under the protection of the vampire nobility. However, when Yuichiro witnesses the slaughter of his "family" by the vampires, he's driven by vengeance to join the Japanese Imperial Demon Army, an organization that fights back against the vampire threat using demon weapons. Yuichiro, now with newfound powers and allies like Shinoa Hiragi, embarks on a mission not only to avenge his loved ones but also to rescue Mikaela, who has become a vampire. As he navigates through battles, betrayals, and the complexities of his new world, Yuichiro uncovers dark secrets about humanity, the vampires, and the very nature of the seraph of the end. (Unreviewed summary by Grok 2)