Gork and Mork
Gork and Mork are the twin gods of the Orks. Ork traits and emotions have a reflection in the warp the same as the traits and emotions of Humans and Eldar do. These Ork traits manifest in the form of the strong, belligerent, and indestructible Ork gods Gork and Mork. The difference between the two gods is very subtle, Gork being brutal but cunning while Mork is cunning but brutal. The upshot is Mork hits you when you aren't looking and Gork hits you harder when you are. The strength of Gork and Mork is too strong to ever be quelled and when confronting the gods of other races they can never truly be vanquished.
Both gods are believed to offer help to individual Orks in battle, but in the grand scheme, it doesn't matter which god is worshipped. Generally, Gork is worshipped by the regular boyz as a more direct manisfestation of brutal power, when Mork is the God of Oddboyz, the cunning Orks like Meks and Weirdboys.
The titanic Ork Gargants are constructed in the two gods' image; consequently, they are living idols and war machines. The Mekboys who build them work from a vision held within their imagination, usually inspired during times of Waaagh.
Ghazghkull Mag Uruk Thraka is the prophet of Gork and Mork, the two gods supposedly guiding his wars of conquest against the Imperium, revealing the best ways of defeating his enemies. This was apparent in the invasions of Armageddon.