Religion is one of the central concepts in Game of Thrones Season 6. Some of the major storylines involve this aspect, particularly that of the High Sparrow’s and Melisandre’s.

For starters, George R. R. Martin’s tomes tell the story of a god called Azor Ahai. He is described as a mythical being from the ancient times who fought against evil forces in an epic battle. He defeats the evil forces with the use of a magical burning sword, which has been blessed by the Lord of Light R’hllor. It is prophesied that Azor Ahai will be reborn when a similar conflict arises.

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The known believers of this religion are Melisandre, Beric Dondarrion, and Thoros of Myr.

The Sun reports fans have suggested that the god depicted in the HBO series may have been inspired by the ancient scripts of Zoroastrianism, a religion that originated a thousand years ago in Iran. Those who follow Zoroastrianism believe that the god, Ahura Mazad, created good and evil—twins that were known as Spenta Mainyu and Angra Mainyu.

Ahura Mazad eventually became allies with Spenta Mainyu as they defeated the evil twin, Angra Mainyu.

An interesting theory that connects the show with this ancient Persian religion involves Jon Snow. According to the theory, Snow may be resurrected as Azor Ahai who will lead the battle against the evil forces.

In the premiere episode of Game of Thrones Season 6, Melisandre is confused by the sight of Jon Snow’s corpse, telling Ser Davos and several members of the Night’s Watch that she saw the Lord Commander in the flames, fighting in Winterfell.

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Aside from the Lord of Light, there are several other religions all throughout the realm. In Westeros, the more dominant religion is the Faith of the Seven. According to Yahoo! News, Bran Stark’s warging and greensight are related to a religion called the Children of the Forest. Finally, the Iron Islands believe in The Drowned God.

Those in Essos believe in The Many-Faced God, which according to them links all the religions in the realm. The Dothraki believe in a deity of their own, referred to as The Great Stallion.

Game of Thrones Season 6 airs on HBO.