Os sonserinos voltaram e lutaram contra Voldemort na batalha final, com Horace Slughorn liderando a investida!
JN: And how much is it that being sorted into Slytherin is, you know, sorted into good guys and bad guys here?
JKR: Well, they’re not all bad, that would- I know I’ve said this before, (JN: Yeah, I remember.) and I think I said it to Emerson [Spartz - Mugglenet.com], they are not all bad, and, well, far from it. As we know, at the end, they may have (laughs) a slightly more highly developed sense of self-preservation then other people because…
SU: Yeah, right.
JN: Yeah.
JKR: A part of the final battle that made me smile was Slughorn galloping back with Slytherins, (SU: Yes!) (JN: laughs) but they’d gone off to get reinforcements first, you know what I’m saying? But yes, they came back, they came back to fight, so I mean- but I’m sure that many people would say “Well, that’s common sense, isn’t it? Isn’t that smart, to get out, get more people and come back with them?”
Pottercast # 131 -- The Leaky Cauldron -- 01.02.08
Nesse contexto, a explicação de JKR me leva a concluir que Phineas Nigellus estava se referindo a Sonserina como um todo quando fez seu comentário sobre "Slytherin ter desempenhado o seu papel" "