Valyrian Steel

The smiths of Valyria made it with spells, the stories say, and some say with dragonfire too. A blade of it weighs less than common steel and takes a keener edge, and that edge never needs restoring. The metal is dark, and the folding shows in it as faint ripples.

The secret went down with Valyria at the Doom, some four hundred years ago. A few smiths, most of them in Qohor, can rework old Valyrian steel, but no one alive can make it new. The blades left in Westeros are few, and the houses that own them pass them down as their greatest treasure, each with its name.

House Stark’s is Ice, a greatsword. The Lord of Winterfell carries it when he does justice himself. The Mormonts have held Longclaw for five hundred years.