MTL - Space Doctor: The National Hero is a Girl - Chapter 40 boy genius

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 his old world, Aiden Ferith was a peerless war hero—feared by nations, revered by millions. Through years of brutal cultivation, he reached heights others only dreamed of. But glory turned to ash when his most trusted disciple drove a blade through his heart, shattering his empire and his soul.That should have been the end.But fate had other plans.Reborn in a world ruled by magic, where mages manipulate elements and battle with dazzling spells, Aiden awakens in the body of a seemingly average boy named Logan Smith. Here, cultivation is unheard of—dismissed as a myth, or worse, a joke.But what they don’t understand will be their undoing.Armed with ancient cultivation techniques that bypass the limitations of magic, Logan begins to carve a path that defies the laws of this new realm. Stronger, faster, and more resilient than any mage, he’s not here to play by their rules.He’s here to break them.Betrayed once.Stripped of everything.This time, he’s not fighting for a kingdom—He’s here to live life on his own terms—to protect those he loves, and finally, to live for himself.

She is the Crown Prince’s fiancee, but on the night of their wedding, an edict was made and she was given off to marry the crippled and paralyzed God of War.

Having been married for two years, he only takes her as an enemy. He never touches her, and even insult her in front of other women, “Si Wan, you are the most disgusting woman in the world.” Facing his ruthlessness, she decides to leave, “Gong Siming, if you don’t love, just let me go.” But he replied dominantly, “Si Wan, of course I love you.” Si Wan is caught in a trance. And he goes on, “I want to love you tenderly every night.”