What is the Cabal in Destiny?

Cabal territory on the Red Planet

What is the Cabal in Destiny?

One of the missions your Guardian will undertake is a trip to the red planet of Mars, where you will might find “the bones of a lost human civilization in the form of an ancient city.” A victim of the terror that brought an end to the Golden Age, the literally golden remains are yours for the taking from the Dust Palace. The only thing in your way will be the Sand Eaters, a group of massive, armored 'War Rhinos' that are collectively known as the Cabal.

Here is a Cabal Legionnaire:

Update: Cabal posted spotted in the wild:

I think this is the Cabal from the Pathways Vidoc: