Thus Spake Zaraborgstrom/GoodandEvil
Universal good and evil is a dangerous concept for people who want to tell stories.
The thing about the Incan priest is, he can butcher a child one day and then throw away his life for a child the next. If you focus too much on "he's evil," it'll be that much harder for you to understand why and when he'll do that heroic thing. For telling stories about him, it's *more important* to know his motivations, stripped of any sense of good and evil.
Exalted is a poor fantasy world for people who want to apply "good" and "evil" labels. It's not that you can't. It'll just lead to conceptual dissonance, because the vast majority of the important, good, and heroic things that people do will be done by people you've labeled "evil."
It's more useful to figure out which of the people *care* about right and wrong, and are capable of acting on that belief. For example: meaningful numbers of Abyssal Exalted care about right and wrong, and are partially capable of acting on that belief. Typical Deathlords, conversely, are pretty much evil bastards no matter what "evil" means, because they're not motivated by principles at all---if you proved to them, step by step, that they're absolutely, incontrovertibly, morally and ethically wrong, they'd say, "That's nice." and feed you to something.