The Side Character’s Hidden Boss! - Chapter 62 - A Call

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.

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

After a tear in reality pulls Kagari Shuya into a white room he discovers a futuristic interface for reincarnating in a different world. After looking through the different races and skills he unlocks a new race, Lucivault, a type of vampire with none of its characteristic weaknesses. All set to start his life in a new world, Shuya is confused to discover that he is enveloped in darkness. As it turns out something went wrong when he was transported and instead of appearing where he was supposed to, he appeared in an underground cave. Shuya faces untold dangers, runs for his life, before finding his way out of the underground world. After escaping he meets his Shishou and begins to learn to fight with a spear. There is also a cute black cat named Rollo.