Orch Religion, ...
for me, this is to much from Warhammer Fantasy (where Orcs develop a destructive energie called Whargh when they are in rage together) and Earthdawn, where they suffer damage when they try to tame their temper.
I think i will make it more this way:
Lord Clay is the god who created us, the orcs. HE made us strong and tough, and in the beginning, HE gave us masters, the lazy elves and the obsolote dwarfs, and HE give us hard labour. So this is what lord clay wants from us, endurance, pride and self- confidence.
But then lord clay sent us a big trial, the foul humans from the south with hords of demons fell into our homeland. Our masters freed us from slavery and sent us into battle side by side with them, so we had the chance to proof pur worth as warriors.
In the midst of war, our former masters showed their true face, they flet from battles cowardly and let us orcs fight alone. Due to this treason, we lost the war, but due to our sufferings and losses, we were rewarded richly by HIM, lord clay. We earnded our freedom and formed our own nations, where we can live by the values that HE learned us most: Pride, Endurance, Confidence. This is the way of the orcs, and when we honour this values, we will rule over hole ravenland once, we will smash our enemies, kill their children and burn their houses.