The Dungeon Seeker - Volume 3 Chapter 3.1

Childhood sweethearts.
The most popular person in school is my childhood sweetheart.

- Description from Novelupdates

In a modern world where cultivators need a place to cultivate or vent their boredom, there are private businesses that set up instance dungeons with the aid of technology and cultivation magic to enable cultivators to train and commoners to experience the life of cultivation. They are called dungeon suppliers.
Xie Jin's one and only dream was to be a dungeon supplier and when his only relative passed away, the relative's inheritance gave him a plot of land and surprisingly, a 'System' Module which the relative had previously used.
With the help of the system, Xie Jin decided to pursue his dream of becoming the number one dungeon supplier.

A striking man of mysterious origin and peerless talent, he looks back at the world, in all its entirety, with utter disdain. And yet, in the treacherous and unpredictable ultimate formation of the Boundless Secular World, he guards a breathtaking ancient qin with broken strings, waiting silently for the destined one to arrive!

Gilderoy Lockhart has just become Minister for Magic of the United Kingdom, and there are several uninvited guests in the office.

Dumbledore: “Minister, I have to tell you with great sadness that Moriarty Slytherin is the most hidden person in the European wizarding world!”

Lovegood, editor-in-chief of The Quibbler: “Look Minister, the Hogwarts Riots, the Himalayan Avalanche, the Gringotts Heist, the World Cup Opening, the Nurmengard Bombing, the Azkaban Defection , the Durmstrang riot, these mysteries all point to one person, Moriarty Slytherin!”

Platinum noble Lucius: “On behalf of the pure blood family, I strongly request the minister to launch a wanted request for Moriarty Slytherin! Oh, my minister, don’t look at me with greedy eyes, all pure blood money is taken by Mori Artie’s gone.”

Gilderoy Lockhart showed his signature smile: “Please allow me to introduce to you my young master, the greatest wizard of all time, the master of dawn and darkness, the master of ice and thunder, the legendary god of magic, Moriarty Slytherin!”

This is the story of a little wizard who only has magic in his heart and becomes the big boss behind the scenes in the Harry Potter world.

- Description from novelbuddy