MTL - Rebirth 2011 - Chapter 25 It matches your niece very well

A man is stabbed by a robber on the run after pushing his coworker and his coworker’s new fiance out of the way. As he lays dying, bleeding on the ground, he hears a voice. This voice is strange and interprets his dying regret of being a virgin by giving him the [Great Sage] unique skill! Is he being made fun of ?!

She, the “godly doctor” of an assassin organization in 21st century, transmigrated into the body of Yun Family’s abandoned, good-for-nothing Ninth Miss. Good-for-nothing? Then she’ll let the world see what a real good-for-nothing looks like. Summoners are legendary? Nothing is impossible in this world! She’ll become the first Magical Summoner.

“A cheat system? Do you take me for a fool? Nowadays, where can you find such a good thing falling into your lap? Scram from my head. Is this is new kind of fraud? Or is this a murderer training system of aliens that contains the ability of hypnotism?”

“No, I am the chaos that whispers from nothingness, the nightmare of all living beings in the Southern Ten Stars, the successor of the unparalleled God and… your elder sister.”

“…I only have a younger sister, I don’t have an elder sister!”

“No, you have one. I am an illegitimate daughter. It’s just that your dad didn’t inform you.”

- Description from Novelupdates

Louie became a mythical dragon that was capable of traveling between Earth and the Otherworld at will.

From this point on, the number of races in the Otherworld became more plentiful. His territory was orderly and clean, with incredible cuisine, countless novelties, and civilization and philosophy ahead of the whole world.

On Earth, his existence caused the rebirth of magic and mythology, allowing him to become the only God.

“I am the Golden King, the Giver of Life, the Champion of Magic, the Weaver of Dreams, the Guardian of the World, the Master of Time. Let mortals bow down before me and look up! Let the Gods tremble in fear before me!”