Defias Overseer

Defias Overseers can be found in the Deadmines tunnels after the Mast Room leading up to the Goblin Foundry. They just stand in a place and look at a broken pipe.

Dialogue

 * Near the entrance to the Goblin Foundry
 * say
 * say
 * say
 * say
 * say
 * say
 * say
 * say
 * say
 * say

Speculation
Blizzard may have made these mobs neutral so that players will have a higher chance to listen to their conversation instead of killing them on sight.