Harry Potter and the Goblet of Fire
How we cite our quotes:
I told you, Harry ... I told you. If there's one thing I hate more than any other, it's a Death Eater who walked free. They turned their backs on my master when he needed them most. I expected him to punish them. I expected him to torture them. Tell me he hurt them, Harry [...] Tell me he told them that I, I alone remained faithful ... prepared to risk everything to deliver to him the one thing he wanted above all ... you. (35.68)
We have to admit, Mad-Eye Moody – or actually, Barty Crouch, Jr. – is probably the single most principled man in all of Harry Potter and the Goblet of Fire. He is absolutely, totally dedicated to Voldemort. He's willing to go to Azkaban for Voldemort. He is willing to spend a year in disguise for Voldemort. All he asks in return is the acknowledgment that he "alone remained faithful" – something that Voldemort does admit several times during Goblet of Fire. Of course, Barty Crouch, Jr.'s principles are absolutely, totally vile and insane, but he sure sticks to them inflexibly. It's not as though principles are good things to have in and of themselves; you can obviously be quite loyal to bad principles. And Barty Crouch, Jr.'s principles appear to be both pure and evil.