D.E.M.O.N.S: Getting Summoned Weekly isn't so Bad - Chapter 1397 - Marigold the Tag Along

Our protagonist Caam is a man from Earth that was reincarnated into this world as a demon. In order to survive, he spared no effort in avoiding the sparks of battle and without noticing it, he became strong himself.

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

Modesty! Honesty! Compassion! Bravery! Justice! Sacrifice! Honor! Faith!He is a lich, yet he upholds the knightly spirit!He is a lich, yet he remains steadfast in his faith of light!“With a formidable enemy at hand, fearless and unobstructed! Daring and loyal, worthy of the Holy Spirit! Loyal and upright, willing to die unyielding! Protecting the weak, never going against heaven's principles!”Standing at the top of the world, no matter how great the storm, nothing can stop him from following the steps of the Holy Spirit! Not even the Holy Spirit!...This is a romantic legendary story of a chatty cat and a lich who dedicates his body and soul to the light!Yes, “romantic,” not deceiving you! That's just how it is!

The countries of Mephius and Garbera have been waging a war for ten years and are trying to put an end to this long fight through a political marriage between the two royal families. Orba, who was driven from his home because of the war and was forced to become a gladiator, looks exactly like the crown prince of Mephius, and it has been decided he will be substituting him during the wedding ceremony. On the other hand, Vileena, the princess of Garbera, has secretly decided to ensnare the crown prince for her own country’s interests.