Hero Regresses with Villain System - Chapter 1: Exalted

My handsome, overpowered dad, who only ever cared about me, ate something strange and turned into the Demon King. He used to be the sweetest, most doting father, but now he’s the final boss?! Because of this, my dad is fated to be killed by the male lead, and I’m destined to die lonely while mourning him. At that moment, I returned to the past and realized that this world is actually a game! I couldn’t prevent my dad’s descent into darkness, but no matter what, I must turn him back into his original self. If I succeed, I can get my loving dad back, right? For now, I need to get close to the male lead, who’s destined to kill my father…! So, I became a Holy Knight and even managed to be adopted as the ward of the Pluto Ducal House—the male lead’s family. …The problem is, I’ve become way too strong. As long as I get along with the male lead, my dad might avoid being labeled as the Demon King. “But that’s strange.” “…What is?” “Your lips… they’re heart-shaped.” “W-what? Don’t look at my lips!” At that, the male lead tried to avoid my hand and ended up rolling under the bed. “Ahhh!” “…?” He’s supposed to be the strongest person who’ll one day kill my dad, but for now, the male lead is just too cute.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

Lucien was chosen by the God of Gamblers to participate in the Heaven’s Gate Project. Their goal was to help save a dying world from destruction, and ensure that it wouldn’t be destroyed a second time.

Unfortunately, things didn’t go according to the God's plan. Lucien’s soul was heavily injured during the soul transfer and on the verge of collapse. Having no other alternative, the God of Gamblers was forced to take yet another gamble to preserve his chosen candidate’s soul and help him find a new vessel.

As if arranged by Fate itself, Lucien’s soul wandered into the world of Solais until it merged with the dead body of a newborn baby that was left to float down a river. With his new identity as Lux, the boy realized that even with the blessings given to him by the Gods, saving a world was not an easy matter.

In a world of Swords and Magic, where adventures run wild and free… the Legendary Saga of an abandoned Prince is about to begin!

Nine Realms Sword Emperor, a legend returns, leveling everything.Genius monsters, trampled underfoot, powerful beings, wiped out with a wave of a hand.If people do not offend me, I will not offend them; if people do offend me, annihilate their entire family.