Ancestral Unity

Since the death of the Dark Lords, the Orcs have had little truck with gods. Instead, they adopted a form of ancestor worship, revering at first the dead who gave their lives in the Uprising. While their faith began with the specific reverence of the parents of forebears of an individual or tribe, in time it grew to consider all departed orcs as a source of wisdom, experience and strength from which the living stood to benefit. The praxis of orcish worship also evolved. For generations, this faith was largely spiritual, practiced through the intercession of speakers for the ancestors, orcs largely able to channel the strength of the departed in battle. Shrines were raised, prayers and hymns were raised. The faith gained recognisable priests, capable of channeling divine magic, and this was curiously suggestive.
The channeling of divine magic is universally recognised as being possible only with the aid of a true divinity, yet the orcs still rejected any god. After a long period of meditation, study and debate, the orcs came to the realisation that while even their greatest ancestors were no more than powerful spirits, their ancestors collectively were something more. Whether they unknowingly absorbed the spark of true divinity from the Dark Lords, or found it in some other way, the collective spirit of the orc ancestors had become a divine entity, dubbed the Ancestral Unity.
While a few orcs of the diasporas have accepted the faith of the lands they travelled to - the gods of the Church of the Eightfold Way or the Gods of Foundation, for example - for most, the place usually taken by gods, be that deep piety or weekly observance or simply someone to blame, is fulfilled by the Ancestral Unity. When communing with the Unity, they typically find themselves speaking with one or a few specific ancestors as representatives of the whole.