I haven’t read every book in the fantasy genre, but offhand, I can’t think of any others where evil monsters become likeable characters. In my series, it’s a slow evolution beginning with Lana’s stay in the dungeon when she discovers her guards have one-letter “names.” When she gives them “real names,” it sparks their desire to be valued as individuals, and that becomes a catalyst for change.
By the end of book two, the breghlin are still crude, but they’re gaining self-respect and a sense of right and wrong. This trend continues in book three, and by book four (which is half-written as I prepare to publish two and three) some of the breghlin have become main characters, taking important roles along with gnomes.
When I began book one, I never expected my monsters to become “good guys.” But like Lana, I couldn’t hate them. Despite their outward appearance and bad behavior, I was willing to believe they could change. Their evolution is ongoing, but some of my “monsters” surprise me with their courage and integrity. I’m glad I gave them the chance to prove themselves.