The Orcs practiced a syncretic religion that was related to the worship of the Creator, as in the Sepulcher of the Creator, but also Muolih the Spreading Darkness, as in the Goblin and Dwarven faiths. Furthermore, many minor spirits were recognized, from ancestors to those posessing trees and streams, though the primary surviving codices note that they all emphasized the paramountcy of the gods of good and evil.
In Orcish, Muolih was called Tirat, the Rebel, while the Creator was called Nyir, which literally means “that which has created.” Their faith was, as a result, sometimes called Nyirtirat, literally “creator-rebel” but more accurately “the rebel and the rebelled against.” It’s important to note, though, that despite commonalities each Orc community and band had its own extremely local interpretation of faith and disagreements up to and including violence were all too common.
Naturally, this changed with the introduction of the Hamurabash by Hamur, which replaced the former religion with a set of ethical and atheistic strictures and emphasizing the memory of departed kin. The bashamalurs who succeeded Hamur were generally successful in eradicating all traces of the former Orcish religion with only a few isolated (and well-fortified) communities harboring so-called taiwa or apostates.
Even as Hamur’s successors agressively spread his message of atheism, equality, ancestral memory, and the militarization of society, there remain significant Orcish ruins in the high desert of the Lrira, predating the Hamurabash, and in many cases even the Sepulcher, deeply carved and embossed with the memory of the old faith.