As peace returns to the demon realm, Anos Voldigoad wishes nothing more than to put his reputation as the Demon King of Tyranny to rest and go back to being a misfit at the prestigious Demon King Academy. Unfortunately, any tranquility is fleeting: sinister demons, kings, and deities plot Anos's demise from the shadows. Rumors spread about the "Child of God," a being whose power may rival that of Anos. To uncover the truth and eliminate the potential threat, Anos must journey deep into the land of spirits. However, the spirit world is shrouded in mystery, and it may only be entered after undergoing a series of difficult trials. With unrivaled power and confidence, Anos braces himself to defeat various formidable enemies with grandiose titles. But he—with the assistance of his trusted allies—will barely have to break a sweat as the true Demon King of Tyranny.

When Demon Queen Echidna begins her invasion of the human realm, the people turn to the hero Leo Demonheart to protect them. Blessed with insurmountable power, Leo easily repels Echidna's army, thereby saving the world. But instead of gratitude or admiration, Leo is met with disdain and scorn from his fellow humans, who fear his overwhelming strength and believe that it may eventually cause humanity's demise. Banished from the kingdom he once called home, Leo wanders aimlessly throughout the land until, one day, he hears rumors of Echidna's efforts to rebuild her army. Hoping that demonkind might accept him as an ally, he returns to the demon queen's castle and offers Echidna his help. Naturally, Echidna immediately rejects him. Still, not all hope is lost, as Leo manages to convince Echidna's four generals to let him secretly work under their supervision. Donning the identity of a masked dark knight named Onyx, Leo solves the demon army's problems one by one—gradually improving the quality of life around the castle. Above all else, however, Leo wants to accomplish one goal: to learn why Echidna started the war in the first place.

As a cultivation genius who has achieved a new realm every two years since he was a year old, Wang Ling is a near-invincible existence with prowess far beyond his control. But now that he’s sixteen, he faces his greatest battle yet – Senior High School. With one challenge after another popping up, his plans for a low-key high school life seem further and further away…

Takemichi Hanagaki's life is at an all-time low. Just when he thought it couldn't get worse, he finds out that Hinata Tachibana, his ex-girlfriend, was murdered by the Tokyo Manji Gang: a group of vicious criminals that has been disturbing society's peace for quite some time. Wondering where it all went wrong, Takemichi suddenly finds himself travelling through time, ending up 12 years in the past—when he was still in a relationship with Hinata. Realizing he has a chance to save her, Takemichi resolves to infiltrate the Tokyo Manji Gang and climb the ranks in order to rewrite the future and save Hinata from her tragic fate.