Responses
I think the first revision is the version where Kim dokja actions impacted the story but he is currently in the 3rd regression of joonghyuk, but since the story start in the 4th one and joonghuyk say that « that guy » (which probably refers to dokja) is not here, it means that the current regression (3rd) failed and joonghyuk had to make a new one (4th). So dokja sees it has a chance to stop the 3rd regression (current one) from failing.

I don't want like major spoilers or anything, but with the whole rivision of the story and the 3rd to 4th term thing what exactly was explained? Cause it confused me a bit.