Triarchism

A philosophy denounced by the Church of the Holy Celestial Pantheon as a heretical sect, but defended by its adherents as a philosophy more basic and fundamental than the worship of particular sets of gods. Triarchists believe that the world is shaped by the interaction of three forces:

• Siddmunn - The civilising force. Order. Progress. The rule of law.
• Vilt - The wild force. Nature and the natural world. Freedom.
• Haddmunn (sometimes spelled heddmunn or hædmunn - The destructive force. Chaos. Entropy.

Whereas The Church teaches that the world is caught in a battle between good and evil, Triarchists believe that both good and evil can be found in all three forces. Some triarchists fight for siddmunn (law) against haddmunn (chaos) while others value vilt above the other two forces.
Triarchism in Ettrea first emerged as a philosophical and theological movement in the final century of the Old Empire, but may well have existed as a coherent philosophy elsewhere on Erdde for many centuries, perhaps even millennia. During the first centuries of the New Empire , triarchism was tolerated by The Church . It was denounced as heretical by Patriarch Gregorslad. Triarchists hid their belief. Those triarchists in the Church went into hiding. Any that were caught were forced to recant their belief in triarchy; if they didn't, they were executed. The persecution culminated in the Triarchist Crusade, a military campaign sponsored by the Church and designed to eliminate the heresy.

Despite its depiction as a heresy by the orthodox Church, triarchists have been worshippers of both the New Gods and the Old Gods (or have had no religion at all in a small number of cases). (Triarchism is pretty much unheard of among Lizardmen with their curious monotheistic religion.) Triarchists argue that triarchism is not a heresy, is not a religion, but is a philosophy. It is a way of conceiving of the forces of the universe that (in their view) in no way contradicts belief in or worship of either pantheon.
However, the 7th century orthodox Church theologian Issacor of Hengen argued in his Diatribe against Triarchism that in its rejection of the good / evil dichotomy fundamental to Church teachings, triarchism can be said to be a rejection of the fundamental moral struggle represented and personified by the Celestial Pantheon and the Devils  respectively. Thus, triarchism (and by extension its followers), was inherently and fundamentally immoral. Issacor argued that triarchists, in their rejection of a necessary fight against evil, were in fact "allies of the Devils". During Issacor's lifetime, the Diatribe remained obscure, but Patriarch Gregorslad was certainly influenced by it when he denounced triarchism as heretical a century later. 
In Ettrea, triarchism is most common in the northeast of the Empire, in Sigsland and the surrounding areas. Consequently, this region was the focus for the Triarchist Crusade .
Among followers of the Old Gods, triarchism is one of several philosophies used to explain and codify the fundamental forces at work in the universe. Since there is little organised worship or religious hierarchy among worshippers of the Old Gods, triarchism is never seen as a heresy - there is no such thing as a "heresy" to worshippers of the Old Gods. Old God worshipping triarchists tend to be more common in exactly the regions where New God worshipping triarchists are more common. Those Old God worshippers attracted to triarchism often identify with it because they feel the struggle between siddmunn, haddmunn and vilt in their own soul. Others feel an imbalance between the three forces and actively try to strengthen one force (usually vilt) against the other two or two (usually siddmunn and vilt) against the other to achieve 'balance'. Both of these approaches to the philosophy are somewhat different to the most common interpretation among New God worshipping triarchists, who tend to be more passive. That is, New God worshipping triarchists use triarchism to explain events but tend not to take actions according to the three forces.
Triarchism is rare in the Synoppeian Empire where the Church of the Holy Celestial Pantheon is itself regarded as heretical. Synoppeian scholars have long looked on triarchism with an interested neutrality.