Shikkaku Mon no Saikyou Kenja~ Sekai Saikyou no Kenja ga Sarani Tsuyoku Naru Tameni Tenseishimashita~ - Chapter 14 Strongest Sage, Teaches Magic

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

In the near future of South Korea, where everything is determined by aptitude tests, the protagonist Kang Moon-soo gets the job of a “Shaman”.“A shaman? What’s that? Do you earn a lot of money? Is it stable?”The profession of shaman has nothing in common with Moon-soo’s aspirations. He ends up becoming a freelance problem solver, a million light-years away from a stable life!Will Kang Moon-soo be able to sustain a livelihood as a shaman?

…Ring! [ The Unique Skill ‘Grand Devourer’ has been acquired! ]

That’s how it first started.
And then… it didn’t stop:

[ The Unique Skill ‘Evolve’ has been acquired! —
[ The Passive Skill ‘Jelly-like Shapelessness’ has been acquired! —
[ The Passive Skill ‘Resistant Body’ has been acquired! —
[ The Unique Skill ‘Dwell’ has been acquired! —
[ The Unique Skill ‘Skill Copy’ has been acquired! —
[ The Passive Skill ‘Mana Perception’ has been acquired! ]

Up until…

[ The Passive Skill ‘Consciousness’ has been acquired! ]

And then I was through—

Normally, monster-type creatures don’t just pop up in some random place—let alone a human place—out of the blue, and without notice.
Yes, if we’re talking ‘normally’, monsters belong more to places like remote, hostile grounds: they ought to be from dark, nasty forests, old caves, or abandoned, ancient ruins.
As I said, it was only so long as we spoke of the usual deal, however. For better or worse, I wasn’t your regular mob.
So, forget about all the remote, uneasy places humans hardly go to—all the abandoned forests, caves, or dungeons I, a monster, should have been from—and picture a bright, lively family restaurant, in an oh-so-peaceful human village. A restaurant where people ate, chatted, and jested together, all having a good time, blissfully oblivious to the fact that, very soon, I would be cutting them all down.

By magic, a monster-type creature spawned in such a place. It was me.
So far, for the few seconds I had been living, it was quite the good life… I got to listen to a fantastic story being told and shared a cool moment with people.
However! Following an uncertain course of events, I happened to be put up against a wall, with a sword aimed at my chest, before I was mercilessly killed.

I, a unique monster, just spawned in that restaurant, with no clue regarding what was going on.
All I knew was that I wanted to live and survive.
Also, I knew I wasn’t your regular kind of monster.
Thankfully, I’d been granted unique abilities before I showed up.
That is how I managed to survive.