I Became Friends with the Second Cutest Girl in My Class (WN) - Chapter 251: Everything’s Fine Now

I started off as nothing, just a mass of consciousness that slowly evolved. Just your average overpowered existence hungry for a multiverse adventure.

After dying in laboratory tests, Klaus transmigrated to a Sorcerer World, in a strange and peculiar character whose existence is an enigma. He knew this world, for it was the world of the novel one of his students wrote. He also knew the character because he created it. But it was a discarded character; it never appeared in the novel. How could he have transmigrated in it? Reality hit him soon after when he was sent to cross through the first test that every sorcerer must pass to awaken his abilities. There, he will have to fight against powerful monsters, which they call Curses, and against other Sorcerers, all to try to enter the select group of Sorcerers to discover the secrets that await in this world and understand his arrival to this and his existence. Just when he thought his journey might be boring, he received a peculiar and mighty power bordering divinity, capable of making him reach unimaginable heights. Although a bit dangerous...

The main character Lei Yu does not have the ability to practice his family’s martial arts. He gets stepped on and tossed around. Due to certain reasons, he leaves the family, coincidentally gains an ability, and makes his own path to becoming an immortal.

Zheng Tan somehow returns to the year 2003, turning into a black cat. Picked up from a rubbish heap by the Jiao family, he is given the name “Charcoal”, and so begins the life inside Professor Jiao’s family. Zheng Tan remembers that he was once a person, but currently his body is that of a cat. He has no way of speaking the human language, but can understand it, and even retains the thinking and IQ of a young 20 year old youth. Read along as he adapts to this new world, and somehow tumbles from a group brawl to catching a thief.

- Description from Novelupdates