Mage Manual - Chapter 13 - : Sword Maiden Descends Beside Me

The orphan Sun Chan was abandoned by her first love. Her foster mother and sister sold her to the village drunkard, where she endured endless torment and ultimately died from exhaustion in the cornfield. After awakening, she returned to being seventeen years old. She vowed to leave the village this life and carve out a new world for herself! Family, friendship, and love, she will strive for them all. Hey, soldier brother over there, why do you keep looking at me?

There are gods in the sky, there are people on the earth, and there are no immortals in the world.

Three thousand years ago, the gods descended.

The cataclysm of the world, the aura weakens, and the immortals disappear;

One hundred and fifty years ago, the gods descended.

The rich Chipa Plateau and the invincible Panlong Ancient City have all been turned into loess;

After another hundred years, I, descended…

But the starting point to unravel all the mysteries, and even the key to survival in troubled times, starts with being a good dude;

Start from learning to hide the front and defend the clumsiness;

Start with an adventure;

Starting from reversing the established fate;

Most importantly, start by entering the dreamland of the gods.

- Description from novelbuddy

After the ‘100-Year War’ between the Necromancers and Priests, an all-time genius who’ll shake the power structure was born. “Am I a rare case or something? Do I have talent?” A potential beyond all imagination. He obtained his father’s undead army and entered the great Necromancer school of Kizen that divided the continent. Geniuses are geniuses, even when gathered among the elites. The research community was flipped on its head by the appearance of a new case. Professors wouldn’t leave him be alone, wanting to make him study directly under them. Officials from all over the kingdom and heads of organizations fidgeted over whether to scout him. “Professor! When can I make a Lich?” “Gimme a break. How talented are you? You’re crossing the line, honestly.” A genius among geniuses had appeared.

God plucked one of his creations from his first Earth and gave him a second chance in another one of his Earths...surprise it is in DxD! Now reincarnated as a perverted side character how will our poor protagonist handle his new identity? Well he probably wont make the choices you will want him to, that's for sure!