That does seem like a question a Dark Witch would ask, and Harry spent enough time in war that that's the first place his mind goes, as reflexive, by now, as how to twist and move his body out of the path of a flash of green killing light. He blinks twice. Reminds himself, very deliberately, very specifically, that this isn't Britain. That he isn't an Auror.

"An Art is 'Dark' when it causes direct harm to people," he says. "The most obvious -- broad category of all that is curses. I mean, we all used them, during the war." He's trying to be even about it. Use of the Dark Arts does not a Dark Wizard make. "Dueling is a lot about the Dark Arts, really, and plenty of wizards and witches do that for fun and learning. But the cruelest ones, for murder, torture, madness, mind-control, and things like that-- well. Anybody who's focusing on that, we consider a Dark Wizard. It's nasty business.

"Of course, there's also wizards who do horrible shi-- deeds, without using Dark Arts all the time. That was less my area." A furrow appears in his eyebrows, a half-dozen names and faces sidling through his mind's eye, none of them worth mentioning or explaining out loud, for reasons somewhat more objective than his weird quick-step to self-censoring a moment ago. His eyes clear and he looks at the witch again. Reaches over to set a hand on the shaft of the broom now, not to pull it back out of her grasp. If anything, to highlight that he isn't. He isn't assuming anything.

But he is a touch wary. "Your laws were different, I take it?"