I'm pretty sure that it's a new story but with the same Main Character and the same power. So basically in this new story, the original story doesn't exist. It's just a completely new story with the same MC with the same power but different plot and side characters. You could think of this as a completely different manhwa with a MC that look like the original MC with a different personality but with the same power and written by the same author.
I'm a lil bit confused; is this a flashback or ...