Yuuichirou Hyakuya is the protagonist of the anime series 'Owari no Seraph.' After a catastrophic event wipes out most of humanity, Yuuichirou becomes a member of Moon Demon Company, a military unit dedicated to eradicating vampires. He is driven by a deep desire for vengeance against the vampires who killed his family. Yuuichirou is characterized by his determination, strong-willed nature, and a sense of loyalty to his friends. Throughout the series, he struggles with his inner demons and the burden of his past, all while discovering the true nature of his powers.