Dualism

The main religion in Horizon is Dualism; the worship of Fos and Dorcha. Fos represents the concept of "light", encompassing traits like, day, charity, fire, creation, order, chivalry, etc. While Dorcha represents "dark" traits like night, war, change, the ocean, death, ambition, etc. The two of them together are collectively referred to as The Attuned.
Dualism draws its roots to a philosophical movement during the Antecean age. After the empire adopted a secular governance and outlawed the worship of the old pantheon, scholars still sought answers to the nature of the cosmos. Ultimately, they saw the ebb and flow of chaos and order that occurred within nature that somehow always maintained a balance and postulated this to be the nature of the universe. The names Fos and Dorcha did not come until much later, and even then, was considered a cult amongst the more philosophical nature of the concept. With the fall of Antecea and the burning of most of their records, the philosophy persevered as an oral tradition, eventually blossoming into the fully fledged religion it is today.
Core Beliefs The fulcrum of all Dualism and its philosophy is that Fos and Dorcha are engaged in an eternal dance/battle. The tempo of this dance fluctuates over time and this is reflected in the mortal plane in natural phenomena, political movements, and more. One or the other may become more dominant in the dance and this too is reflected in the mortal plane. The most obvious and frequently occurring of these instances is the changing of the seasons.
Fos and Dorcha are embodiments of the energy that created all things
As Fos and Dorcha are equal yet opposing forces in perfect balance, so too will the world always return to equilibrium.
The souls of the faithful are brought to live in peace in Fos' domain, but are shepherded there by Dorcha, who's domain encompasses the passage from this life to the next.
Lastly, it is believed that the Attuned dance falls violently out of sync every so often, usually resulting in a hard reset. Many believe this could have been what befell the Antecean Empire; siting the War for the Eye as a battle between Fos and Dorcha's avatars.
Shepherd and Rapture's Influence. While the origins of Dualism predate the War for the Eye by at least a few decades, Antecea's cataclysmic collapse and the relentless passage of time has done much to muddy the water. Shepherd and Rapture became the blueprint for the idea of Fos and Dorcha, who were attached to the philosophy of "In all things, there is harmony and struggle" that was the framework for dualism. There conjoined Oculus Infinium inspired the Dualist swirl and the pair's coinciding ethos influenced the domains of Fos and Dorcha.
Overtime, what started out as two feuding (albeit extraordinarily powerful) friends transformed into a battle of divine avatars for the fate of the Antecean Empire. For this reason, it is common belief among followers of Dualism was it was this battle that caused the Empire's decline.
The monument left behind by Lonelei and his Night Blades further cemented the idea that these two were divine in nature and that the impassable doors held religious significance. Eventually, religious texts proclaimed that the doors led to Fos and Dorcha's domain and that one day they would open and the Attuned would reset the world again.
In addition to their influence on the primary religion, several cults branched off with more extreme views of what the pair stood for. The most notable of these was the Cult of Rapture, who believed that "Fos's" avatar was betrayed and sealed away behind the doors of Metran Peak (that in reality held back Shepherd and his undead army), and that when they opened, She would return and wreak havoc upon the world.
The holy symbol for the Attuned is a swirling vortex. Statues and depictions of the deities often show the two of them intertwined in a dance or fight with the Attunement floating between them.

Dualism Hierarchy There is no singe leader of the Church of the Attuned. Rather, High Priests of the major temples meet yearly in Crucible to discuss religious doctrine and the church's goals for the coming year. Otherwise, smaller cloisters and individual churches make their own decisions, though most practice very similar rules and traditions.
Within an individual church though there is:

• One high priest. He or she is in charge of all church proceedings. Wears blue robes with red trim
• 3-5 bishops. Each one is in charge of a specific section of the church. Wear blue robes with silver trim
• Any number of priests. These men and women are the workforce of the church and tend to all churchly matters from delivering sermons, providing acts of public service, tending to the sick, and so on and so forth. Wear blue robes.
• Acolytes. Those training to become priests. There are usually two or three for every priest and assist in their duties. Where white robes.
• Clerics. A cleric can be of any rank and is a term used to refer to one who practices divine spellcasting. Often clerics of the church are ranked priest or higher.

Major Dualism Holidays The solstices and equinox of the seasons are revered as holy days. Generally, the week leading up to them are celebrated with festivals and other merrymaking. Spring and Autumn represent peak equilibrium while Winter and Summer represent Dorcha and Fos, respectively.
March 1st: St. Merridan's Day. A celebration of the life and death of the Dualist martyr Abigail Merridan, a cleric who refused to submit to elven oppression and sparked a crusading fire that lead to the "liberation" of Crucible.
November 15th: Novitium. A day dedicated to the "anniversary" of the new age. Acknowledged by lighting only half the candles of a celebrating institution. Celebrates the everchanging nature of the deities but also reveres those who lost their lives to the changing times.
July 31st: Jubilus. A day of revelry and merry-making. A hold over from an Antecean holiday that celebrated the god of celebrations, Vinum.The cyclical nature of Dualism is acknowledged by the exchanging of gifts.