Bloodhound's Regression Instinct - Chapter 187

The end of the world is coming, the world has undergone great changes, and everything has changed. Plants, animals, and even insects, as long as there are living things, have mutated.
Become more powerful, and even evolved supernatural abilities, such as chickens and ducks that can fly to the sky, such as cats and dogs that can breathe fire.
But only humans, without any obvious changes, seem to have fallen from the top of the food chain to the bottom of the food chain overnight.
Any creature that can open its mouth to eat can treat humans as food.
But fortunately, this world has not completely killed humans. Gradually, humans discovered that they had the ability to cultivate compatibility with other creatures.
As long as it has a high degree of compatibility with some powerful mutant creatures, it can be used for its own use to achieve the purpose of protecting itself.
Fang He is a person who is very compatible with mutant animals, but it is also because of his ability that he has changed from the strongest to the stupidest.
Fang He, who was reborn, said, “Hmph, this time…”

- Description from novelbuddy

Liola—the best assassin in his world—has vowed to kill no more. He was being chased by an assassination organization when he accidentally dropped into a parallel universe: through a dimensional gate and into poor teenager Kaiser’s apartment. Instead of going to the government shelter for lost dimensional travelers, Liola and Kaiser wind up going to school together.

Liola has been trying his best to live the life of an ordinary person, but after certain things happen one after the other, he begins to realize that being an ordinary person could be harder than being an assassin.

My name is Kaelith Yurei , and I am a first-year student at the Shin'ō Academy in the Soul Society. I have a friend who is destined to be quite famous in the Soul Society; his name is Sōsuke Aizen.Unlike this ambitious and idealistic friend, my goals are quite simple: through hard work and diligence, I aim to graduate and become a seated officer in the Gotei 13, from which point I will… I bounded with who!?Whenever Aizen enhances his strength, my power automatically synchronizes to match his level.Therefore, what I need to do from now on is very clear.“Sōsuke, you need to work hard. As long as you put in enough effort, I can live the life I desire!”