Hugin and Munin were the ravens of Odin. He would send them out into the Nine Worlds each day to learn what was transpiring.
When Malekith began his endgame in the War of the Realms, he sent a band of Dark Elves to assassinate Odin. While Odin managed to repel his assailants, either Hugin or Munin was killed but was later brought back to life.
