Welcome To Hell, Dear Wife - Chapter 19: Rotten Kingdom.

The magical girl who made the wish of “destruction of this world” came to Ke Xue’s world, and Kewpie became a little Kewpie.

Being chased by someone holding a knife at the beginning, Shuangyue fell silent.
In a world without witches, how would she purify her soul gem?

Originally, he just wanted to be a good and hard-working employee in the winery, but the old man always liked the whole brainwashing operation. Suppressed by the world consciousness, for her own pure land, Shuangyue decided to go to his red square and black square, she would smash the dog world consciousness.

The protagonist is not a good person (highlighted), the three views have been distorted in the magic circle world, not a red square.

Little Cupid: You are my magical girl, and I am your Cupid.
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Rescuing Matsuda Cat and Jingguang Cat, the protagonists directly built a gray empire for Jin Jiu and Sister Bei.
Hagihara and the squad leader are still dead, because the protagonist was not there at the time.
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Do not dismantle the original cp, bring your own cp (but there is no obvious emotional line).

Content Label: Teen Conan
Search keywords: Protagonist: Frost Moon Saya ┃ Supporting roles: Gin, Zhufu Jingguang, Matsuda Jinping, Edogawa Conan, Maorilan, Kayao (Shirazawa Nozomi), Little Cupid (Ruby) ┃Others:

- Description from novelbuddy

A world where the [Demon King] was defeated by a [Hero] that came from another world. People carelessly forgot about their fear of the [Demon King] and of monsters, living in peace.

In a forgotten and run-down cave in the mountains, a new monster that should not have been born was given birth.

The monster’s name was the [Black Ooze]. It was nothing exceptional other than its black color, an ordinary slime.

However, this slime had the special characteristic of being able to take the abilities of the living things it swallowed. It preyed on an insect that had paralytic poison, as well as other animals. Following that, it attacked a human, obtaining his knowledge and [Desire].

Before long, the monster established its target as the female mage that came to explore the cave.

This world still wasn’t aware.

Unconditional obedience to him? Dream on! Regrettably, after marrying Tang Yuchen, An Ruo's daily thoughts were of escape, escape, and more escape! Someone grew furious, “You want to flee? The only way out is if you die, or I perish!” Fine, she chose death! Yet he laughed wickedly, “Woman, do you intend to kill the son in your womb?”

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates