The Athar or Defier is a faction that believes that the gods do not deserve the worship of mortals, nor do they have any right to pass judgment over mortals as the "powers" are powerful, but have limits and thus do not deserve worship.
They believe in empowering others to make their own way in life, without some supernatural figure to protect them. As such they help run areas of Sigil in many different ways, some help run the schools, others write tracts, but mostly they "debate" with the various priests throughout Sigil.
The Athar work to unravel the dark of divinity, and release any information they find to the public at large.
To see others freed from the influence of these so-called "gods".
They are located within the Shattered Temple, a temple to a long dead god in the Lower Ward
The Athar has been around as long as most factions, so don't go asking for the entire history of their doings (or undoings). The faction began centuries before the Great Upheaval, soon after two cutters - Dunn and Ciro - encountered on another in Sigil amid the ruins of the Shattered Temple. The Shrine existed in its broken state even back then, but Dunn and Crio looked at its decay from different viewpoints.
Dunn's had lost both his wife and daughter due to his worship of the Poseidon, his wife was lured by the riches of his chief after he paid his gods' tithe. His daughter had been sweep away to the plane of Arborea by the powers proxy. Dunn saw the temple as a way to make Poseidon as dead as Aoaskar, the power once worshiped in this temple.
Ciro had more of a Philosophical bent. He too had lost his treasures to a god - Loki - and god's religious hierarchy. But he'd found he liked his unencumbered life. Roaming the multiverse as an itinerant sage served him more than maintaining a house. But Ciro wondered why a power would need his priests with gold, should require the belief of worshipers to feed his immortality if he were really a god.
The texts say that Ciro would have ignored Dunn in his mental meandering if Dunn hadn't mistaken Ciro for a follower and Aoaskar and attacked him, the resulting fight and words lead to an alliance between the two, they would return within half a year with tales of definance against the powers and some like-minded recruits.
Demography and Population
Many Planars in the Great Ring serve a power and would never join the Athar. This fact makes the Lost less multiracial than some other factions, such as the Believers of the Source
and the Free League
. Bariaur, Half-elves, humans, tieflings, dwarves, elves, gnomes, and halflings are all well represented. Githzerai seems few and far between, though: The majority revere either their race's nameless wizard-king or the Legendary Zerthimon as a god.
There are rare accounts and sightings of celestials working with or for the athar, where ever this is true or not is unknown, but some Athar has been known to claim to contact or have a contract with one celestial or another, in an attempt to discover the real truth if nothing else.
Wizards, priests, thieves, druids and even Paladins are members of the order, and they each have their own reasons; Wizards believe that the Gods produce some form of tainted magic, druids insist that the powers interfere with the natural cycles of the multiverse and want to see them operate without interlopers, Paladins hope to convert all beings from worship of their idols to reverence for the true although unknown source of all majesty. While Priests look beyond the powers in search of the Greater Unknown god.