Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 10 - 10-15. Red Iron Plate

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- Description from Novelupdates

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 a world where six once-allied nations now stand divided, the kingdom of Myralis, a symbol of self-sacrifice, has fallen into oblivion. Centuries after its mysterious downfall, Caelum, the last disciple of a forgotten deity, embarks on a perilous journey to restore his nation's honor.Guided by the enigmatic teachings of his vanished mentor and armed with the legendary Seal of Abnegation, Caelum must navigate treacherous politics and face champions from rival kingdoms in a deadly tournament that will decide the fate of the world.As ancient secrets resurface and alliances crumble, Caelum discovers that every truth hides a lie and every ally could become an enemy. His quest could either unite the Six Nations—or precipitate their destruction.Will he master his heritage and fulfill the prophecy that marks him as Myralis’s savior, or will his choices doom the world to chaos?

In the eyes of outsiders, Hyuga Yuuto is a genius in the traditional sense of the Hyuga family:

Tough, strong, gentle, and calm, he is a partner worth relying on at all times.

However, no one knows, in countless silent nights.

The young genius of the separation family stroked the caged bird engraved on his head and fell asleep with the sharp needle in his mouth, fearing that in his sleep he would reveal the madness and anger deep in his heart——

“What Uchiha Itachi can do, I, Hinata Yuuto, can’t dare to do?”

- Description from novelbuddy