MTL - I’m Fighting Back In the Ninja World with Spells - Chapter 39 there are monsters

Growing up in the slums, deprived of freedom, being enslaved by his parents and thugs, all Lucifer wanted was a life of freedom, a life that he could do whaver he wanted, not being ordered by anyone.And then luck came to Lucifer when he awakened the system, and even luckier was that he was able to raise his Destiny Rank to Unpredictable.But in return...he was turned into Freedom's Most Loyal Slave

‘Less than a month old… I became the the great empire’s treasured princess…!’

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

A master assassin transmigrates into an interstellar era.