Harry Potter and the Deathly Hallows
Dudley, Harry's Muggle cousin, has grown up and – shockingly – didn't turn out so bad. Though he's none too sharp, he turns out to have a heart and even a (bit of) mind of his own. Though dimwitted, he's the only one in his family smart enough to realize that he and his parents really are in danger from Voldemort, and he wants the protection of the Order. Though it seems that Harry has entirely written off his cousin (and aunt and uncle) by Book 7, on parting with the Dursleys, Dudley is worried for Harry's safety. He shows that he disagrees with his parents that Harry is "a waste of space" (3.96), and even thanks Harry for saving his life (from the Dementor's Kiss in Harry Potter and the Order of the Phoenix). Gosh, seems like Dudders might be a decent guy.