so what you're saying is Dean is a Hufflepuff... gone bad?
Maybe? Like, I don’t think he has much in the way of loyalty anymore, unless it’s to himself and his goals. He has some regard for Sam, but in the way I have regard for my laptop: it’s important, it’s irreplaceable, it’s been a constant companion for years…but when it’s gone, I’ll get a new one. When Sam’s gone, Dean can replace him with [Charlie, Benny, Lisa, Cas], and it’s not the same, but it’s workable. Hell, he literally replaced Sam with an angel. Repeatedly. And had no remorse for it. If he was ‘just’, he wouldn’t kill parents in front of their kids. So no, he’s neither just nor loyal at this point. It’s not that he’s a Hufflepuff gone bad, it’s that he is not a Hufflepuff. He was at one point, but no more.