I'm looking for ''ugly'' or fat or unattractive mc that stays that way and doesn't change

Kekkaishi is a pretty classic shounen but it has a very average protagonist who doesn't change much through the story, in that aspect. It's a pretty good take on shounen tropes and the best of its kind imo. The protagonist is very likeable because of how he is (girls don't like him, he's seen as a loser / lunatic by other people, etc.)

Ressentiment

and maybe Angel Densetsu ?
The MC supposely not change from beginning till the end, but the mangaka/author artwork really change dramatically that the MC face are very different if you compare 1st vol with last vol. 😂

Saikyou Densetsu Kurosawa, it´s sequel and many works of the author in general.

I also read EU/US comics and am a librarian.
Manga-Masters, My ANN-Lists + Imdb

maybe Kawaii Hito (SAITOU Ken) ? He doesnt change through out the manga but he gets called "scary" instead of "unattractive". I hope you still like it though its a very cute manga 😀

aaaaaaaaaaaaaaa

"A bouquet for an ugly girl" has a very plain girl as a MC and its very nice 🙂

Now, these haven't ended yet so there might be some changes later on...

Saikyou Yuusha wa Oharaibako: Maou ni nattara zutto Ore no Musou Return - Humans think he is ugly, but the demi-humans compares him to a really cute elf... somehow... and said elf finds him downright attractive... but he still fat and kind of orcylooking.
Tsuki ga Michibiku Isekai Douchuu - He is considered ugly by more or less everyone in the world he arrives in.

~4400 manga completed
~1700 ongoing...

Asahina Wakaba to ○○ na Kareshi, which is almost complete (at least according to the LN).

the webtoon [url]Cursed Princess Club[/url]

I've just start try to read this,
High Score Girl
but it reminds me of this thread. 😅