It started out quite well and the characters are quite fun to follow but the overall snails pace the story and character development goes at and the repetitive fights get more and more boring as it goes on. Had plenty of potential but it just seems the writers can't think of a story to follow so they just pump out fights against the same characters wearing a different face and clothes.
There is also some romance for the main character but even that seems to enjoy just keeping the status quo, there are a few moments where it seems it's going to advance and in the next moment everything that happened is never brought up again and they go back to the same state as before, it gets quite infuriating to be honest.
The best part about this "story" is the relationship between the numbers and the mc, and the few flashbacks we get into his life before returning to Korea, but even these moments start to get repetitive after about the 120 chapter mark.
If you enjoy meaningless fights that are well drawn and being drip fed a story on lifesupport this is the manwha for you.