Quel'delar

Story
Quel'delar is an elf sword that was transfered to northrend by queen lana'thel in order to destroy the lich king. However queen lana'thel didn't survived and the sword was abandoned at the frozen heart of Icecrown mountains.

Later on (as seen on Drumans vs Lich King part 2), Drumans was the chosen to take out the sword and purify it.