The Demonic World I designed - Chapter 743 - 734: The Battle Application of Art Calculation!

This is a story of a modern man returning to ancient times, returning to a real world without any extraordinaryness, and slowly rising by relying on the ability to attribute all data.

- Description from novelbuddy

A generation’s War God, once overlooking the world with disdain, had fallen into disgrace because of a conspiracy, becoming a mere son-in-law. However, what nobody had expected was that it was all part of his grand scheme, and when the winds of change blew, he, the king, returned, with the power to overturn seas and move mountains, as a dragon ascended to the heavens!

Three years ago, in the land of Reinbulk, a Legendary Hero was summoned in the Kindom of Leezalion and he succeeded in repelling the Demon King. Now, five students are summoned back into Reinbulk by the Kingdom of Luxeria to fight against the Demon King and the demon army. Unlike the other heroes, Yashiro Yuu has no magical affinity and the Luxeria Kingdom has no intention on acknowledging his existence or returning him to his world.

When 18-year-old Kyle Conner arrives at his aunt's for a summer holiday, he expects relaxation and freedom. Instead, his life is forever altered when he crosses paths with Lilith, the demon of lust and second-most powerful entity in the underworld.Forced into a dark pact, Kyle is transformed into a demon and gifted with a mysterious system that promises immense power. But this newfound strength comes with a deadly price: Kyle must hide his true nature and navigate the treacherous world of demons, all while being hunted by Lucifer and other malevolent forces.As Kyle struggles to control his newfound powers and unravel the secrets of the system, he discovers his ultimate goal: to overthrow Lucifer and bring about a new era of peace. But with the forces of darkness closing in, Kyle must confront the darkness within himself and make impossible choices to survive.Will Kyle be able to master his demonic powers, outwit his enemies, and fulfill his destiny? Or will the weight of his newfound responsibilities consume him, dooming humanity to eternal darkness?