By sheer coincidence I seem to have read two books with asexual protagonists, in the past week. They were actually acknowledged, within the text, as being asexual, embracing it as a sexual identity.
Since I remembered
https://forum.choiceofgames.com/t/where-are-the-aces-asexuals I thought that people might be interested in discussing asexual characters in movies, books, tv shows, games, etc, examples of good and bad representation, and whatnot, and if anyone’s got any recommendations.
Every Heart A Doorway by Seannan Maguire, is a novella about a boarding school, and what happens to people after they return from fantasy worlds, how they cope with the real world and leaving their fantasy worlds behind. There’s a mystery thrown in. It’s got an asexual protagonist, and also got a trans character.
Banner of the Damned by Sherwood Smith is an epic fantasy novel, with an asexual protagonist, in a world where a number of the characters aren’t straight. It’s the story of Emras, who is a scribe to a Princess, who eventually learns magic, and a whole lot of politics and stuff thrown in. (And which half the book blurbs seem filled with spoilers.)
Deed of Paksenarrion by Elizabeth Moon is a fantasy trilogy, with an asexual protagonist. It’s the story of Paksenarrion, who begins as a sheepfarmer’s daughter, joins a mercenary company, and eventually becomes a hero. It was one of those series that I used to reread when I was a lot younger, and I really enjoyed.
Clariel by Garth Nix (suggested by @Scribblesome) has an asexual protagonist. “The story’s great though personally I was a little disappointed that she’s portrayed as a general ‘loner’ type.”
Edited to Add:
Incidentally, I do think there’s a difference between asexual characters, like those presented in Lord of the Rings, where many characters are shown to have no romantic/sexual interests, and characters who actually acknowledge their asexuality in the text.