A novel at creche K'lirr focusing on Lae'zel's training would be interesting. Wherein she's forced to cut the throats of her cousins at the varsh's command. Wherein she has to kill her classmates to survive.
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A novel focusing on Shadowheart and leading ultimately to her mission to steal the artifact would be good... except, imo, it would take enormous talent to pull off well. I could see it being done poorly.
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Gale, meh. His story is too over the top for my taste. I'm not all that interested in reading about a fantasy of a super prodigy wizard having sex with a goddess. Little too Kvothe, perhaps.
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Karlach, I don't know. Folks seem to like her. She just doesn't click with me. I don't understand how she could have gone through ten years of forced hell and come out of it with such a rainbow personality. I would have expected her to have more scars, both externally and internally.
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Wyll. Clearly, there's plenty of material. It's just a matter of whether or not an author could get readers to like him enough to stick with the story. I agree that his character needed work from the early access version, but I think they may have corrected a bit too much. He went from being somewhat of a joke to being too much the generic hero.
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Astarion's days, or rather nights, with Cazador. This would be tough, imo. Not much character agency, not many redeeming features, and full of torture.
