MTL - Mr. You, Please Dote On Me - Chapter 14 You and I are just friends

In the legends that were told, ten thousand years ago the twelve demon kings wreaked havoc upon the world, almost completely destroying it. Ten thousand years later, the late arriving Bella discovered that she had been screwed over by her reincarnation, the ranks of the Saviors are already filled and she has to change teams in order to pass the days. Having her gender changed into a beautiful girl… she endured that, not being able to join the righteous side and obtain cheat abilities… she endured, but what she could not endure, was that the world that she had transmigrated to was toxic beyond belief. No one here does their rightful jobs properly, be they heroes, demon kings, or creator gods… in fact, Bella felt as if they all had also started with the wrong faction!

My past life: Ordinary. Mediocre.

Wei Yuewu is the unloved daughter of the powerful Marquis Hua Yang. On her way back to the capital city to marry her fiancé, she becomes the target of a ruthless assassination led by her fiancé, Marquis Jing Yuan. With the help of the Prince of Yan State, she narrowly escapes from one disaster after another and returns to the capital. Determined to avenge her enemies and unravel the mystery surrounding her engagement with Marquis Jing Yuan as well as the death of her mother, Wei Yuewu makes a deal with the Prince of Yan State. However, just as she has triumphed over all her enemies and is about to reach the acme of her life, she deliberately destroys her own future and becomes an exile of her own…

- Description from Novelupdates

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.