Industrial Cthulhu: Starting as an Island Lord - Chapter 29:

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.

“Even if this universe is truly nothing more than a brutal bloody shadowy forest, we Cultivators will burn all that we have just to give off a single weak flickering spark in the darkness!

Jack Smith’s life ended rather abruptly. Spinning out on ice while driving a truck was not the most magnificent method to depart this earth. A mediocre man he had led an ordinary life until his death. Now with a second chance at life, he decided that this time he would be exceptional. This time he would finally live up to his name. After all, a jack of all trades is a master of none but ultimately better than one.Armed with a system and determination to do his best he sets out like any other reincarnated soul in another world to find his place and achieve great things. There is just one small problem with getting started in this endeavour . . . he is yet to be born!Welcome to a progression fantasy with a twist. What might you be able to achieve if your race to the top began before your body had even been born?Join our hero as he masters the language, magics and skills of the Compass Kingdoms but his first great challenge will be learning to walk once more. . . . .Warning 1: Be prepared for the MC to spend an entire book's worth of words and time as an infant but hopefully you will enjoy it nevertheless.Warning 2: Grandfather is legally abusive to MC for a couple of chapters but he is removed from that situation around chapter 30. To be edited out some time in the future.

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.