Nuclear-powered Sword Immortal - Chapter 984 - 764: All World Alliance

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

After dying, you wake up and realize you've been reincarnated as a background character who is judged as human trash.The decision to change your destiny comes instantly.Discovering that your identity isn't as simple as you thought, you feel favored by the heavens when you manage to become a powerful character.Katase: You won't fool me. I'll expose you for the pervert you are.Murayama: ...Thank you for saving us.Issei: Motohama, what happened to you? How are you so powerful?Rias: If you join my peerage, I wouldn't mind being yours.Sona: You beat me in the game. That means you're now my fiancé.Yasaka: Honey, Kuno wants a little brother.Kaori Houjou: Shinji-kun, let's go on an adventure.Kaede Kazama: Shinji-kun, thank you for saving me from that ball.Rie Sawada: Shinji-kun, I'll wait for you. You'll be my future husband, fufufufu...Changing known history and taking it in a direction not even his eyes could perceive, he didn't stop no matter what. Not even the other world was safe from his clutches.Lexia Von Arselia: My hero, and my future husband...Shinji advances without stopping.“I, Shinji Motohama, swear here and now that I will reach the top of both worlds.”

I was reborn as the villainous daughter, Yumiela Dolknes, in the world of an otome RPG game. Yumiela only had a small role in the original story, but after defeating the Demon King, she will appear as the Hidden Boss with a bonus specs to solo fight the Hero party.

Having a gamer-spirit, I’ve been raising my level since I was a child. By the time I enter the academy where the game stage is, I was level 99.

I wanted the heroine and the capture targets to defeat the Demon King, but they just flirted around and didn’t raise their level. Moreover, they treat me as if I’m the Demon King just because I have dark hair and use dark magic.

It’s a story where I aim for peaceful days.

Imagine being forced to live, after death, as incorporeal bodies trapped in a vast space of nothingness for thousands of years, with nothing to do but exchanging past memories with other cohabitants (read: weirdos). Everybody wanted out, but there was no way to leave the Void…

Until one day, a young man was finally summoned, as a powerful but reluctant mentor, by a bubbly and motivated but completely naive young girl. Baiyi, finally out of the Void, was the only one who could save all of the other 32 souls from their prison and his summoner might just be The Key to their freedom.

However, Baiyi had to use the techniques and abilities the other souls had taught him throughout the years, and together with his own extensive knowledge of anime and game tropes from his shady and dangerous past as an otaku, to face the biggest challenge of them all: training the clumsy young girl he was forced to partner up with… into a competent sorcerer!

This is a story of heroic adventures, cunning strategies and romantic tales. How will our MC thrive in a world completely strange to him? Where will his ambitions and abilities take him in the palace?

- Description from Novelupdates