If you like Game of Thrones, you'll love this. This has got to be one of the best fantasy romance stories I've read in any medium, and the amazing art makes it even more of a treat to read. I haven't read every fantasy BL webtoon out there, but I'm pretty sure King's Maker would be one of the best of the genre.
Art: 11 / 10 (Gorgeous character designs, coloring, attention to details and textures that's just Even the sound effects and use of perspectives are evocative, and helps pull you further into the story)
Story: 10 / 10 (this webtoon /will/ keep you at the edge of your seat. Highly binge-reading worthy)
World-building: 10 / 10
Side Characters: COMPLETELY LOVABLE, really adds to the story. Also, this story has yet to introduce a single female character that I didn't adore, but special mention goes to Randalph's handsome half-sisters and Dame Gareth, who is a gift to bi(cep)sexual culture.
King's Maker