Slytherin, the hat had almost put him in, and his similarity to Slytherin's heir Riddle himself had commented on. But he was beginning to think this wasn't because he had "un-Gryffindor" qualities that fit only in Slytherin, but because the two houses - normally pictured as opposites - were in some fundamental ways quite similar.

Ravenclaws in battle, he had no doubt, would cooly plan the sacrifice of distant strangers to achieve an important objective, though that cold logic could collapse in the face of sacrificing family instead. Hufflepuffs would sacrifice no one, though it means they sacrifice an objective in its place.

Only Gryffindors and Slytherins were good at sacrificing those they loved.

But with one friend who had lost weeks to the hospital wing and who could so easily have lost her life instead, with another mourning..., with himself going into battles he barely survived, and making decisions he should not have to make, he dreaded what they might be called upon to sacrifice next.

And he decided: he would do much, to see that it did not happen.

From Myst Shadow's excellent fanfiction, Forging the Sword.