The Unknown Soldier

The Unknown Soldier is an undead, former Alliance skeleton found in a small graveyard at Beggar's Haunt of Duskwood. He can be seen kneeling next to a grave, presumably his own.

Speculation
While he is hostile to both Alliance and Horde and is clearly undead, it is unknown if the soldier is aligned with the Scourge. Due to the fact that he is kneeling at his grave, this may suggest that he still possesses knowledge of his former life or of the fact that he is no longer living.

Trivia
The name "The Unknown Soldier" is likely homage to Tombs of Unknown Soldiers, which are built in many nations in honor of unidentified soldiers killed in battle.