Cliff Strive teaches ancient history at an elite Tokyo university, where his charismatic and friendly demeanor makes him popular, especially with female students. He possesses the unusual habit of abbreviating entire sentences into acronyms. His presence at the school is deliberate; he targets Shinta Mizumura, the last descendant of the ancient Romuald bloodline of vampire hunters, to ensure Shinta's safety. Cliff himself belongs to this lineage. His mission also involves hunting Lilith, a vampire who has enrolled at the school. In daily life, Cliff appears cultured, cheerful, and approachable, building positive relationships with students and colleagues. However, when confronting vampires, his personality shifts drastically. He harbors a deep revulsion towards them and takes distinct pleasure in torturing and killing them, revealing a sadistic side starkly contrasting his amiable public persona.