Honestly, I think the core conflict for a skeleton devil protagonist is this profound, aching disconnect between what they are and what they remember being. They're a being of bone and shadow, instinctively feared or reviled, but clinging to the echoes of a softer self—maybe memories of warmth, a name, a face they can no longer feel. That internal dissonance is everything. Does she fight her nature to reclaim a ghost of humanity, or embrace the monstrous power she now wields to protect the fragments of her past? I'm reminded of how the protagonist in 'The Wandering Inn' handles skeleton characters like Az'kerash; there's this endless tension between cold, logical immortality and the emotional echoes that won't fade. The external conflict often stems from this: the world sees a monster to be slain, while internally, there's a person screaming inside a cage of ribs. The drive isn't just about survival; it's about whether the self is defined by soul or structure, and if you can even have one without the other.
It gets even messier if they retain their old moral compass. Imagine knowing murder is wrong, but your very existence now requires a kind of spiritual consumption to sustain your consciousness. Every act of necessary 'evil' for survival corrodes that remaining sense of goodness. That's a slow-burn tragedy I'd read in a heartbeat. The most interesting stories don't have them quickly accept their fate; they trip over their own feet (metaphorically, since they're bones) trying to act human, failing, and causing unintended horror, which just deepens the isolation. The emotional core is grief, but it's grief for your own lost self, which is a uniquely devastating kind of loneliness.