The Temple Guard are the guard units in charge of defending the Temple of War in the Fissure of Woe. they are part of the Eternal army and their units are all Eternals.
The Temple Guard was formerly lead by Lord Khobay but he betrayed them and, along with some Traitorous Temple Guards, helped the Shadow Army overtake the temple and imprison the Eternal Forgemaster.
After completing the quest Defend the Temple of War the Temple Guard are set free and they will resume defending the Temple of War. They can provide some help in clearing out the area south of the temple by luring enemies back to them.