Colosos at the Argent Tournament Grounds wants you to bring him Winter's Edge.
That's the last time I ever spar with a death knight.
In southern Crystalsong Forest, overlooking the Crystal Vice's exit, you will find Lord Everblaze. Kill him and take the everburning ember from his corpse.
Bring it to the center of Winter's Breath Lake in northern Howling Fjord, and use it to free the maiden encased in ice. She is the guardian of an ancient sword and will award it to whoever frees her.
Prove your worth and earn the weapon that she has guarded for so long, <name>.