The art of this Manhwa is beautiful and I have checked the same artist's work to determine the fact (that for me personally) they make beautiful characters, great line work, though myself being not very well-versed with art, drawings like these is quite in par with my personal taste.
But reading works like these is when I realize not everyone who are able to draw are good writers. I believe, they rack their brains to come up with a theme/idea for a story and they cook up story boards and I am sure it takes up a lot of time and energy but end up writing a story that doesn't make such sense with characters of minimal depth.
Being tagged with yaoi/shounen-ai we come expecting two men falling in love with the added benefits of drama which either binds them forever or detaches them in the end (whatever may be the sub-genre, horror, psychological, slice of life etc).
So the least we can expect is to sense chemistry between the love interests and sorry to say this, this story lacked it to an embarrassing degree.
I have nothing against morally-grey characters but writing characters takes a lot of time and actual interest to read up on and study human psychology; this is where a lot of artists fail.
The characters were half-baked, the romance was bland and the plot (even though a well-thought out theme) badly executed.
for me two straight guys who get into fights constantly, there is no way these people will fall for each other, even if the author threw them into a locked room or a locker