MTL - Naruto Lineage Theory? Trash - Chapter 725

A 30-year-old NEET is reincarnated into the body of an otaku that choked to death on instant noodles. As he comes to grips with his new life, he realizes that this world is subtly different from Earth. The denizens of this world are far better looking, and this new world also possesses futuristic technology as well as mysterious Yin Yang masters!

After reincarnating, he realized that he was endowed with a miraculous game-like system, which enables him to increase his own stats and transcend the limits of the human body. This system even has a game-breaking ability to save and load in real life!

In this new world that’s akin to a 2-D game, he just wants to enjoy life and head for a glorious future… However, he is quickly embroiled in a complex plot. Can he unlock his true potential and utilize his system to break the shackles that confine him and discover the truth about his previous body’s circumstances?

- 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.

Cain was living his best life as the leader of CROSS, a gang ruling Zone A, District 4.At 21, thanks to constant cigarettes and booze, he looked older than his years. He didn’t finish college or have a job, but he made a living through “guard fees” from local markets and his shady side business.One night, his life turned upside down when a shooting star crashed through his window, transforming into a cute fairy girl in a pink dress and rabbit hat, who declared herself the Idol-Idol Goddess!Now, Cain has to juggle being a gang leader and a rising idol star. Can he balance both lives without blowing his cover?[RPG System Style. No Harem. Drama. Romance. Face Slapping. Idol. Magical Realism. Urban Setting. Beautiful Female Lead. Strong ML. Smart ML. Handsome ML. Cold ML] XD

Chang An is a sub-beast who, despite having the talent for the sword, did not have the constitution to support it. And his savior, Hua Yi, is a beastman on the run for his life.

This is a story about how two once innocent children had to grow up in such a cruel beastman world.

- Description from Novelupdates