My Master Only Breaks Through on the Edge of Death - Chapter 427: 400: The Black Smoke Giant

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

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.