Hell Teacher: Jigoku Sensei Nube

Meisuke "Nube" Nueno, a teacher at Doumori Elementary School with deep knowledge of the occult, struggles to keep his students safe from mysterious threats. When one of them is pulled into another world, Nube meets a strange spirit that sends him back in time to correct a past mistake. Though he succeeds in setting things right, these bizarre incidents hint at something far worse lurking beneath the surface of Doumori. To shield those he cares about, Nube must face his own inner demons and unravel the truth behind the growing supernatural danger.