MTL - Tome of Blood - Chapter 4 -4- I became a vampire?

In his past life, Ethan Steele was an ordinary man living in a modern world—working a dead-end job, struggling through the monotony of daily life, and haunted by regrets of missed opportunities.At the age of 23, his life came to a sudden, unexpected end in a car accident. As his consciousness faded into darkness, he was sure it was over.But fate had other plans. In the divine realm, the God of Fate watched over the balance of life and death.Ethan's untimely death was a mistake, an anomaly that diverged from the preordained path of his destiny. It wasn't yet his time to die, and so, the god decided to give him another chance.“You were meant for greater things, Ethan Steele,” the god's voice boomed. “To correct this error, I will reincarnate you in another world—one filled with magic, swords, kingdoms, and adventure. You shall be reborn, but you will not remember your past until the appointed time. There is, however, a... complication.”By divine error, the god accidentally bestowed Ethan with the Harem God System without having any idea about it.This system is a powerful, reality-bending system that would allow him to charm and seduce influential women to build his harem, growing in strength and power with each conquest.“Your memories of Earth will return on your seventh birthday. I hope you enjoy your life here in this world”And with that, Ethan's soul was transported to a new world.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates

Without noticing it, a man called Bill passed away, but then he realized that his life wouldn’t end that way and soon he was reborn as Billy in another world. Billy was already satisfied enough that he retained his memories, but the surprises didn’t end there. He was born with a weird power that granted him the chance to convert mana into experience points and transmit it to all sorts of things.

Things were looking pretty good until he noticed that he was born in an impoverished and rustic village that was facing their imminent extinction in the hands of creatures that he had never heard of before and other tribes that had all sorts of abilities. Before he could learn how even to crawl, Billy had to find a way to help his tribe. Otherwise, they will be annihilated before he can even become strong enough to stand.

Billy’s journey will be much different than he had imagined. Much farther away from Earth than he had originally thought, Billy will have to adapt to a new environment where his tribe is at the bottom of the food chain. Will he be able to grow up safely and try to change things for the better for his new family and friends?