Amazing, simply amazing. No real spoilers in this review. Also, please pardon any grammatical errors, English is not my native language.

After I finished chapter 90, I started with the novel because I couldn't wait for the next chapter. I will talk about the Manga but I will mention a few things about the novel.

The story is very typical, nothing outstanding about the theme. What does make a difference, without a doubt, is the way the story is told. The manga does a good job at portraying the novel but, of course, it cannot emphasize all the aspects and depth of the novel. The story gets surprisingly interesting after the character gets a "job". It is something I completely did not expect but after finishing the following chapter I could not be happier.
The characters feel very real, they make decisions like a real person would; not the typical cliched Japanese characters. Hence, the Korean origin of this piece of art. When I read it and got into the story, I eagerly waited for the decisions the MC would take. Several of them are surprising. Some of them I agreed with, other I did not but I was able to understand his point of view.
(Novel) The main character goes through a fantastical metamorphosis throughout the story but at the same time he remains stagnant. He keeps his more inner values and morals intact although knowing that he has to make the hard choices when it really matters.
The art is fabulous. It really matches the quality of the story. Nothing else to say about that.

Please read the novel of this story, it will not disappoint.

With nothing else to add, I can honestly say that it is one of the best stories I have read in quite a while.