MTL - The Upgrade System of All Realms Starts From Conquering Naruto - Chapter 35 Natsume Yang, don’t mess around

Gu Zuo: Are you sick?

Gongyi Tianheng: You have medicine?

Gu Zuo: You’re sick!

Gongyi Tianheng: If I say I’m sick, can you cure me?

Gu Zuo: If I say I have medicine, would you want it?

Gongyi Tianheng: However much you have is how much I want.

Gu Zuo: However much you want is how much I have.

Gongyi Tianheng: Then bring it all out.

Gu Zuo: …

Simply speaking, a scaredy-cat shou transmigrated and had to think of a way to survive. He had a golden finger called Medicine Refining System, but unfortunately, he didn’t have the ingredients needed to refine medicine and level up.

A great young master to an empire’s preeminent clan had a super high IQ, but his potential for cultivation was low. Unfortunately, pill refiners were too hard to develop, and weren’t restricted to his personal service. But he could acquire plenty of ingredients.

Two people, one was sick and one had medicine. Therefore, the one who was sick kept the one who had medicine, and everyone was happy.

Taking place within a world of Measurements―superpowers owned from birth, with most being absolute trash.A world involving numerous secret organisations looking to take advantage of those rare and remarkable few possessing exceptional powers.When there exists Forbidden Knowledge better left unknown.When the discovery of said knowledge results in the inevitable; a world-ending catastrophe.‘Ignorance is bliss.’Fighting against the unrelenting persistence of the one who knows all.Before the tragic fate of the world repeats itself once more.―He must be stopped.

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.