MTL - Ancient Thunder Dragon Spell - Chapter 1165 : History of the Qing Emperor

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

- Description from Novelupdates

The world has ended. I’m the only survivor left in the shelter. But by my side is the world’s most advanced AI, Artemis.

Hogwarts is a strange place. The demon king who failed plastic surgery was eliminated from the job search. The white-haired old man wearing two layers of wool socks is still too cold in summer. The potion professor who never washes his hair is afraid of going bald, and the key keeper loves to play dragons!

William wanted to spend seven ordinary years, until that night, the door handle of the college lounge was stolen…

(Book Friends Group Number: 605848137)

- Description from novelbuddy

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.