Engineer "Spark"Overgrind is a gnome emissary of Odesysus' fleet and secretly a servant of Kael'thas in World of Warcraft.
History
At one point, Overgrind betrayed the Alliance to the Kael'thas and the Burning Legion and became a spy. He was enlisted in Odesysus' fleet and sold them out to the Venture Company. A Draenei adventurer was sent to find out who the traitor was. The adventurer disguised as a tree saw the gnome meeting with Geezle which reveals that Overgrind was the traitor. Overgrind was killed by the adventurer sent by Odesysus.