Blackstone Code - Chapter 151:

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.

“Who would've imagined that I, the mighty Burning Heaven Dragon Emperor, would be reborn as a mere beast?!”As one of the...

I had a supporting role in a modern fantasy.

The loyal dog of a villain with an angel’s name, Cheon Sa-yeon, and an unfortunate supporting character who died on his behalf, Han Yi-gyeol.

In order to escape from Cheon Sa-yeon and survive, he must use the protagonist, Ha Tae-heon.

But Ha Tae-heon, who he thought of as a lifeline, was infinitely indifferent to him. Rather, Cheon Sa-yeon showed interest.

But besides that, something strange happened.

The events that occurred in the original story had advanced, and the gate and monster levels had risen. Even the people were “different” from the original.

The original version I was trying to use was wrong.