After Becoming My Archrival's Guardian

[Arrogant, Seductive Demon King Bottom & Morality-Model Savior Top Who Plays Favorites]

The Demon King Buzhou was sealed away for tens of thousands of years. When he finally awoke, human society had entered an era of hyper-advanced technology.

Bad news: After being sealed for so long, the Demon King had lost his fearsome powers.

Good news: His nemesis, the Savior who could stand against evil, was now trapped in the body of a four-year-old human child!

Demon King Buzhou could have crushed him with one hand. Unfortunately, fate had other plans.

...He was forced to become his nemesis's guardian.

The Savior carried the will of an ancient, mighty being, but was now stuck in a mortal body. He needed three meals a day, couldn't sleep with the air conditioning too cold, had to eat specially prepared children's food, and could even get sick. He needed someone to give him medicine, too!

This was a centralized civilization where the world had united under one government. It was a society ruled by law and built on technology, with no demons or monsters, and no need to revere so-called gods or devils.

And yet, the rulers of this hyper-advanced age seemed to come from ancient times as well.

How had the world gone from a chaotic age overrun by demons to a civilized era?

Why did an unfulfilled contract exist in the timeline when the Demon King had never appeared?

How had his nemesis's true body been left behind in the old civilization of the past?

To make good on an ancient pact, the Demon King joined the Savior in his search for his true body. Guardian and ward traveled back through time and traced the past, gradually uncovering the truth.

A hilarious collision between a lost old world and material civilization~

The truth is, don't believe in the truth.

[Arrogant Demon King Bottom Who Doesn't Know He's Flirting X Savior Top Who Seems Unmoved but Is Secretly Brewing Inner Demons]

[Quick note: 67% plot, 33% romance]

Theme: Never stop striving!