So many novels have very handsome/beautiful mc's, so few have those that are genuinely disgusting to imagine, much less look at. Way of the Devil was quite bold in the ways it had the protagonist look, but it was still at the cope-out-he-can-effing-shapeshift level, Atelier Tanaka had the middle-aged busaman who often got mistaken for a lizardman, which was fine and appreciated and, of course, I'm sure there's a million R18 novels here with ugly af ntrmen... which I am not interested in reading. Any other novels with mc's who look genuinely unattractive at least, frightening and traumatising at most? No R18, no echii, no harem and the mc stays ugly throughut the whole story.
Reincarnated Swordmaster's cow dung. He is not just ugly, but stupid as well. I have no idea other than comrade mao to read the work.
The Nostalgia Chick wrote a parody book of Twillight about a girl having a paranormal romance with... Chtulhu
My Disciples Are All Villains maybe? the main character is the one who transmigrated into the body of hundreds year old man.
Idk if this counts, but Kumo Desu ga, Nani Ka has a female protagonist who is literally a dungeon spider the whole story. I haven't read it, so I don't know how other characters in the world react to her appearance.
Actually... There's a BL story where the MC was tortured and had his face and body scarred up in a way that makes him pretty unappealing from what I remember. It's called Spring Trees and Sunset Clouds.
This is a manga, To your eternity/ To you the immortal. The story is about the mc(a spirit thing of sorts) that possessed the body of a dying wolf. He gained the form of the wolf and then meets the boy that was raising the artic wolf. The boy dyes and the mc takes his form and travels away from where they are now to follow the boy’s dream from when he was alive. He meets new ppl and gains new forms, I wouldn’t say he’s ugly but there was one arc where he gains a grotesque form. It’s a heartwarming and disturbing tale.