Hell Teacher: Jigoku Sensei Nube 1x26

As Nube struggles against a demon far more powerful than himself, it becomes clear he cannot defeat it alone. If he dies here, the Nube that Hiroshi knows will cease to exist. However, Hiroshi and his friends can only watch in bewilderment. Despite the odds, Nube refuses to give up. He prepares for the worst when suddenly, he senses something strangely familiar.