Through years of misuse, makeshift repairs with whatever materials were available and constant use, it is a rusty, highly stylized suit of power armor. The left arm of the suit was replaced with the sleeve and glove of the raider iconoclast armor, a brahmin skull substituted for the left pauldron and various bits and pieces of metal were used to patch holes in the structure of it.
It is aesthetically identical to Ashur's power armor. Everett notes this as being intended by the armor's designers. Pitt natives came to see Ashur as a god, and made this set of armor to emulate the way their god looked. It was one of the original suits of power armor worn by the Brotherhood of Steel. While they are identical in design, their effects vary.
The following is a comparison of Ashur's power armor and the tribal power armor.
This body armor has the greatest increase for AP (15). If one combines it with Ledoux's hockey mask (+25 AP), they will receive +38 AP (two are lost from the Agility decrease), then if one adds the use of jet, ultrajet and Nuka-Cola Quantum, one can get up to +130 Action Points.
This armor may be the best choice for V.A.T.S. focused player characters, however, one may also consider Lag-Bolt's combat armor instead to gain an additional 3 DR while only losing 5 AP (3 AP net due the Agility penalty).