The Sage's Otherworldly Teacher Life仙尊の異世界教師生活; The Immortal Emperor Will Live as a Teacher in Another World

A peaceful life is suddenly disrupted by the appearance of a mysterious old man. “You were once a great Sage,” he declares to Kouki Chiga, an ordinary high school teacher. However, Kouki has no memory of such a past. To reclaim his lost memories and the loved one he has forgotten, the strange marking etched on his right hand becomes the key. Now, his journey to return to the heavens begins!