In a lot of ways, Cedric Diggory's death does a better job than anything at illustrating exactly what Voldemort is, because Diggory isn't Voldemort's enemy. They've never met, he isn't a Muggleborn, and his family doesn't have a history of fighting Voldemort. Yet Voldemort orders him killed all the same, without hesitation or remorse. Why? Because he was there: an extra person where they only really needed Harry. He's really one of the first major characters to die in the series, which throws everyone for a loop and shows us all that this isn't little kids messing around with giant chess sets anymore. What makes it even worse, though, is that Cedric seems to be a legitimately nice guy. The only reason he's killed at all is because he and Harry are engaged in sort of a chivalrous, fair play good guy contest and neither of them wants to take all the credit for winning the Triwizard Tournament. And let's not even talk about Dumbledore's eulogy or the gut-wrenching sobs of Mr. Diggory, because I just don't think I'm emotionally prepared to relive that.