The characters are all very distinct. Long hair and glasses are easy ways to make your characters stand out, but hey, it works.
Especially when Conor had long hair, but even with short hair he's very memorable.
Especially One's character design, as he has much more masculine features than you often see in bl.
Ivan really sticks out in my mind because tanned MC's are so rare. The emphasis on facial features relating to your tribe also helps the character design (Alek really does look like a snake at times, no shade.) Hyun's design is less memorable, but that kind of makes sense as he is the soft cute uke classic, but that trope is a feature of the owl tribe.
Param's eyes are so pretty. He's been slimmed down in recent chapters which is frustrating. Hwi is one of the few trustworthy redheads in webtoons so he sticks out to me!!!
Hakdo's character design is so good. His tan contrasted with his hair is so pretty.
Who can forget Mr Kang's eyebrows.
Is it a copout to add a character with an accessory that makes them stand out? Perhaps. Gonna do it anyway. Tsugumi is so instantly recognisable.
Both characters have memorable design despite falling very much into buff seme, tiny uke tropes.
An obvious addition to the list, since we so rarely see "ugly" characters (although I think he's quite cute? I love some freckles).
King's Maker