I have came up with 3 ideas, each a different novel, to develop and adapt a character from;
The Gunslinger by Stephen King, as apart of The Dark Tower Series.
It's a series that I enjoy reading, and has plenty of material to work from, with a likeable protagonist and fascinating character development.
The Gunslinger is the first in the series, which introduces Roland Deschain as the Anti-Hero. His goal is to seek The Dark Tower, which serves as a crossing point for parallel universes, though his motives for doing so change throughout the story and is driven by his Ka-Tet that is similar to that of Karma.
This fantasy world is set in the old west, though uses old tales, demons and magic. Such as Roland's dual revolvers having been made by the metal of Excalibur, a fictional sword from other tales that serves as a reference in this fantasy world.
The Black Company by Glen Cook has a powerful wizard and an interesting background to adapt into a game.
The Way Of Kings by Brandon Sanderson has an interesting world with a lot of material to adapt into a game.