Summary
Takao Hiyama serves as an educator at the school attended by Yuki, while secretly operating as the serial killer haunting the surrounding area. Very little is revealed about his personality, as he is limited to only four lines of dialogue throughout the entire series, all of which occur when he discovers and expresses surprise at encountering Yukiteru. As the Third diary owner, he possesses the Killer diary, which predicts the location of his next target. This tool offers a strategic advantage for those aware of other diary holders' identities who wish to launch preemptive attacks, though it lacks utility in other scenarios. When stalking his prey, Hiyama conceals his identity behind a heavy trenchcoat, hat, and mask, carrying a large machete as his primary weapon. His name is derived from Vulcan, the Roman god of blacksmithing.
