"Tris, is there anything you can do about the thing in Harry's head-I mean, in his soul?" Ignoring Dumbledore's dry joke, Sirius remained more concerned about Harry.
When he first arrived, Tris had already mentioned that there were some "impurities" in Harry's soul.
Tris wasn't supposed to know that it was a fragment of Voldemort's soul, so he hadn't called it a soul fragment outright, but an impurity instead.
To his surprise, Dumbledore had explained its origins directly. When Voldemort had tried to kill Harry all those years ago, Lily's Protective Magic had rebounded the attack.
"Voldemort's soul was already unstable from creating Horcruxes. That failed killing caused another piece of his soul to break off. For reasons we cannot be entirely certain of, that soul fragment attached itself to Harry..." Dumbledore had explained at the time.
"Perhaps some of his traits might therefore manifest in Harry as well, though they do not seem to have appeared."
Harry looked utterly lost. He had no idea what traits Voldemort had. Although Harry had discovered very early on that he could speak Parseltongue, he had never connected it to Voldemort. He had only thought that his ancestors might have had some connection to Slytherin-a very strong possibility.
Most importantly, he didn't know that Voldemort could speak Parseltongue either.
At Sirius's question, Tris thought for a moment before saying, "It shouldn't be difficult. In a sense, Harry could be considered a Horcrux-a living Horcrux. But he's much more fragile than an actual Horcrux. Those are incredibly difficult to destroy."
"Is that a good thing or a bad thing?" Harry looked unimpressed.
"A good thing, obviously," Tris said matter-of-factly. "At least we won't have to destroy you completely, the way we would have to destroy a Horcrux."
"Well, thanks for that." Harry rolled his