The thing with ASOIAF/GOT, is that not only is everything so many shades of grey morally, but there's a definite sense that truly great, world-changing individuals are to be considered 'above' petty notions of morality, as is a similar theme in a lot of fantasy. Ambition is to be lauded, even if it drives some abhorrent acts.
Take the original Aegon Targaryen for instance. Together with his sisters, he conquered the Seven Kingdoms, bringing peace and a new Golden Age of prosperity to an eternally in-fighting backwater. If not for him, there would be no Iron Throne to fight over; and, while he may also have employed lots of negotiation and careful diplomacy to accomplish unity in Westeros, at the end of the day, everyone gave up their crowns and bent the knee so that they wouldn't see every last man, woman, and child in their kingdom burned to ash in Dragon fire. Going further back, Brandon The Builder, who raised The Wall, the largest man-made structure in the known world, and founded the Night's Watch, in order to keep the rest of the world safe from annihilation at the hands of the Others. However, it's implied that he accomplished this by enslaving the Giants, and even if that isn't true, there's no denying that a lot of people, who back them would have been considered Northmen, Brandon's own kin, were simply abandoned on the wrong side of The Wall once he'd picked his spot to build. In case you needed another example, Azor Ahai, who's legend claims sacrificed his own lover, murdering her personally and tempering the sword Lightbringer in her blood, to become the hero the world needed him to be.
It's clear that these men are to be consider neither wholly good or wholly evil, but can you even place them on some kind of middle-ground in between, or do the enormity of their deeds make them transcend such a simplified scale? If there is 'evil' in Westeros, it is smaller, and pettier than that. Disgusting deeds done by disgusting individuals, not in the name of saving the world, or building a civilisation, or even just attaining power for its own sake, but rather just because it satisfies them in one way or another; and even in those few examples, you must ask yourself if they are only what they have become thanks to what they have been made by others.
Take the original Aegon Targaryen for instance. Together with his sisters, he conquered the Seven Kingdoms, bringing peace and a new Golden Age of prosperity to an eternally in-fighting backwater. If not for him, there would be no Iron Throne to fight over; and, while he may also have employed lots of negotiation and careful diplomacy to accomplish unity in Westeros, at the end of the day, everyone gave up their crowns and bent the knee so that they wouldn't see every last man, woman, and child in their kingdom burned to ash in Dragon fire. Going further back, Brandon The Builder, who raised The Wall, the largest man-made structure in the known world, and founded the Night's Watch, in order to keep the rest of the world safe from annihilation at the hands of the Others. However, it's implied that he accomplished this by enslaving the Giants, and even if that isn't true, there's no denying that a lot of people, who back them would have been considered Northmen, Brandon's own kin, were simply abandoned on the wrong side of The Wall once he'd picked his spot to build. In case you needed another example, Azor Ahai, who's legend claims sacrificed his own lover, murdering her personally and tempering the sword Lightbringer in her blood, to become the hero the world needed him to be.
It's clear that these men are to be consider neither wholly good or wholly evil, but can you even place them on some kind of middle-ground in between, or do the enormity of their deeds make them transcend such a simplified scale? If there is 'evil' in Westeros, it is smaller, and pettier than that. Disgusting deeds done by disgusting individuals, not in the name of saving the world, or building a civilisation, or even just attaining power for its own sake, but rather just because it satisfies them in one way or another; and even in those few examples, you must ask yourself if they are only what they have become thanks to what they have been made by others.