The Lord of the Cleansing Fire

According to a legend, when the first human colonists were visiting the abandoned town, later known as Aermoor in contemporary Greenhills, they saw a strange glow emanating from one of the palaces. Inside they met an individual sitting near a great bowl of fire. Being asked who he was and what he was doing there he answered: I guard the Eternal Fire; as long as it will flame in this place, so long this city and your kin will endure - and then he disappeared.
The astonished humans discerned a divine sign in that incident and designated some men to keep an eye on the fire.
Aermoor was the area's only brick town, so lots of people were coming to settle down. Some of them traded, others dabbled in craft. With time non-humans also came. They did not bother the priests due to not causing harm to the city, paying taxes and sometimes even worshipping the Fire.
The priests are strongly against using magic, as it should not sully the place where the Cleansing Fire flames. Sorcery is considered as a blasphemy, excluding the ones who have obtained an official permission or trade imported magical items.
Cleansing Fire is a symbol of hope, enduring misfortune, light pointing the way in darkness, heralding progress and a better tomorrow. The Cleansing flame guards the city from the forces of evil that could threaten its citizens; everyone believes that any monster could break within the walls and undermining this belief is considered to be a blasphemy since it is questioning the power of the Cleansing Fire. At first the forces of evil were considered to be merely the truly monstrous races of the world but in time it grew to mean anything non human. Humanoid races like elves, dwarves and halflings are tolerated but looked down upon and ostracized.
The followers of The Lord of the Cleansing Fire often burned supposed witches at the stake for using the blasphemous dark arts of sorcery.
Even though this religion originated in Aermoor, Greenhills, it has spread to most of the nine kingdoms and according to custom every temple, church or shrine has to have a flame burning at all times originating from the flame at the first fire in the Palace of the Flame in Aermoor and if it ever goes out they have to travel back to the source to rekindle the fire. Many devout followers pilgrimage to the Palace of the Flame at least once in their life.
The church also has a military arm, known as The Flaming Hand, that both functions to solidify their power within society but also hunt supposed witches, conducts witch trials and burnings.