MTL - Invincible Exchange System - Chapter 66 Sword Spirit!

The mountain village boy accidentally got the fairy gourd, and he rose step by step to cultivate immortality and longevity.

Ripe elixir, mortal flow.

- Description from novelbuddy

Chen Minhao found himself transmigrated to a parallel world in China, and he even became an idol trainee. By virtue of his efforts in mastering his IQ, EQ, and his looks as his weapons, he became a celebrity with a huge fan base step by step, and ultimately became a global superstar that conquered the both the fields of acting and singing.

- Description from Novelupdates

Dumbledore always believed Voldemort was the greatest threat to the wizarding world until a thousand-year-old vampire showed up at Hogwarts with the deed in hand—“A thousand years have passed, and Hogwarts' lease is up!” said Dracula. “Headmaster, you wouldn't want your students to be homeless, would you?”“What do you want?” Dumbledore asked gravely.“Anything interesting.”“Well, I think the position of Defense Against the Dark Arts professor is quite interesting!”...And so, Hogwarts gained a professor who couldn’t be dismissed.McGonagall: “Albus, I don't think Professor Dracula's teaching is suitable for the poor children!”Dumbledore: “There's nothing I can do, no one can fire him.”...Draco: “My father is a governor, I'll have him get you fired!”Lucius slapped Draco on the head, “Mr. Dracula, Draco speaks without thinking. Please, don't fire the Board of Governors!”...This is the story of a vampire who lived too long and found amusement in the wizarding world out of sheer boredom.

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.