Ser Alliser Thorne from A Clash of Kings is the former swords master from Night's Watch. He delighted in tormenting Jon Snow and in particular Sam Tarley. He is sent to take the hand of the wight that tried to kill Lord Mormont (Jon Snow saved him) and to ask Tyrion for reinforcements to fight the wights (White Walkers). Tyrion can't spare any men so he lets Thorne take prisoners from the dungeon.
