Global Demon King: Starting as the Abyssal Dragon - Chapter 45

Amamiya Hiroto is unlucky. His life consisted of misfortune after misfortune, culminating in an unlucky death during an incident on a school boat trip, trying to save a girl he barely knew. After death, he met a god of reincarnation who requested that the hundred or so dead passengers—one of them being the girl he tried in vain to save—be reincarnated into another world.

Oscar, a destitute young boy, died in a tragic accident and was reborn in the forgotten realm. As a member of the lowly Birch tribe, his solace comes from the fragments of a guardian's spirit, residing in his soul. After the decimation of his family in the hands of a powerful race known as the dreads, he embarked on the part of revenge, leading him to the path of transcendence.

The protagonist, having degenerated into a “loser” after being unable to find employment, gets caught up in someone else’s attempt to commit suicide-by-train and ends up traveling to another world. The numerous cheat powers he demands from God are all granted to him. But contrary to expectations, these powers bring about disastrous consequences for the protagonist.

Having reincarnated into another world, the optimistic protagonist (Yuuri) starts his(her) heart-warming training days with his(her) teacher.