I gave this a go as the fantasy BL concept sounded interesting, but it wasn't executed very well. The plot was basically Eunil, the human, liking Lewellyn, the demon, not realizing Lewellyn is his ex-best friend Mujin.
The characters were annoyingly dense. Of course, with the plot summary I expected there would be a difference in how Eunil treats Lewellyn and how he treats Mujin, but the stark contrast between their treatment makes Eunil a hard-to-love character. Also, Eunil's infatuation with Lewellyn is childish, starting from a one time encounter in Eunil's childhood. The reason Eunil came to hate Mujin wasn't convincing. Though Eunil had a reason for hating Mujin, the level of dislike shown towards Mujin is too much for such a reason.
Throughout the story, Eunil comes off as stupid and childish. Watching Mujin dance around whether he should reveal his true form was also annoying. The newly introduced boss' nephew was also annoying. The situations and coincidences that keep happening felt slightly forced. Seeing situations where Mujin and Lewellyn switch and Eujin still not realizing was frustrating.
At least the ending was acceptable.
The art was alright. The art throughout the webtoon didn't reach the level of the cover art, but that's understandable as the author won't be able to spend as much time drawing many frames as drawing one cover art. Overall the frames were drawn alright.
I would recommend this if you want to read with the feeling of knowing what's going to happen, then a weak feeling of "a-ha, finally," with great annoyance throughout your reading experience.