Yeah, that's definitely an NPC You can tell because it has the same armor, style, and generic body as the others.
And, you'll notice you see no health/skill bar with the health/mana orbs at the bottom, which most likely means that this was cropped from an original screenshot- so the player probably just got cropped out since he/she isn't the focus of the image. Or it was just a test run picture from the developers without a player, since they wouldn't need to abide by that rule.
1UP: Can you talk about the state of the classes? For example, is every class -- even the two that you have yet to reveal -- playable in the game right now?
JW: No. The fourth class is playable in game but is using a placeholder model -- one of an NPC, actually. And all of the skills are what we call "programmer art" because we haven't implemented actual skill effects. So that one is just in gameplay testing for us while we determine signature skills. The fifth class, we're just about finished concepting it and are about to start building it.