I Am In Marvel - Chapter 1: Oh Mother

Ernest Quelt, the alchemist renowned for his unparalleled mastery of alchemy, has perished.But his death wasn't a noble sacrifice in battle, nor the result of a failed expedition—it was a betrayal. The very comrades he trusted most turned on him, driven by envy of his growing power.Yet fate wasn’t entirely cruel. With his final breath, Ernest's gaze fell upon the tube that contained his greatest achievement: a perfect artificial being known as the Homunculus.More than just a vessel resembling a human, this creation harbored the power of a catastrophic beast—one that had once nearly brought the world to ruin.

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

Akira Tsukihara was a romance author who despised love. Though she wrote best-selling novels filled with idealistic romance, she harbored nothing but contempt for the genre and the readers who adored it. Love, in her eyes, was a lie—an illusion that blinded people from the true forces of the world: power, betrayal, and ambition. One night, in a fit of frustration, she cursed love itself... and woke up trapped inside one of her own stories.Reborn as Aira, a nameless peasant girl in the Kingdom of Seraphis—a world she had meticulously crafted—Akira quickly realizes that reincarnation isn’t the fantasy dream she had written about. She isn’t a noble, a princess, or a heroine blessed with beauty and power. She is a nobody. A commoner, struggling to survive in the harsh realities of the medieval world she had once designed as a mere backdrop for her grand romances.As Aira, she faces starvation, endless labor, and the crushing weight of insignificance. But Akira was never one to accept fate. If she couldn’t escape this world, she would rewrite the story on her own terms. She would carve her name into history—not as the lovestruck heroine of a cliché romance, but as the mastermind who would bend the world to her will.In a land ruled by noble bloodlines and political schemes, where the romance tropes she once loathed play out before her eyes, Aira sets her sights on one goal: destroying the very ideals of love that had imprisoned her in this wretched world.Even if it means becoming the villain of her own story.

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