Gakusanjin

is a rock demon whose form is of a mountain and owns the Fuyōheki, that conceals his energy and lets him sleep eternally. However, Naraku steals the Fuyōheki to conceal his heart. He then helps Inuyasha and his gang to find Naraku, giving them a demonic aura crystal: if the aura disappears, the Fuyōheki will be near (The gang promises to return the Fuyōheki in return). He is later killed by the Gyōja.

岳山人 Gakusanjin