Hiruko the Goblin
A school was constructed on one of the Hell's Gates, where legions of demons await their release to roam the Earth. Hiruko is a goblin sent to Earth on a mission of reconnaissance. He decapitates students to affix their heads to the spider-like bodies of demons. Hieda, a professor of archaeology, and Masao, a troubled student, investigate the gruesome deaths and eventually engage in combat with Hiruko.