Dailan Heresy
The Dailan Heresy, founded roughly two thousand years after the fall of the Eldar and named after its greatest scholar, Dail, holds that the gods serve mortalkind, not the other way around. It is the philosophy that emerged from Dail's Singular Question: what possible need could near-omniscient beings have that could be provided by infinitely weaker beings like mortals?
Finding no answer, Dail (and later, the circle of his disciples that called themselves the Dailan Scholars) flipped the assumption on its head, that the gods obtained their power (although from where or what is unclear) solely so that they could serve mortalkind, as a tradeoff for that power. In its essence, Dail concluded, gods made a bargain (also known as the Dailan Promise) with the universe, that in exchange for vast power they would take upon themselves the mantle of mortalkind's creation, and protect and provide for them.
As mortalkind grew in numbers, however, the power of the gods grew divided--that power was finite, and divided among gods, immortals, and many of those same mortals. Thus, the gods' ability to protect and provide grew thinner and thinner against the entropy of the universe and the machinations of the forces of evil or chaos. This meant the gods could protect mortalkind less and less often, and could only shield them so far from the cruelty of the universe.
Suffering, then, comes when mortals rely too heavily upon the gods' increasingly-limited ability to respond directly to mortal demands; gods lack the power, Dail reasoned, and therefore cannot always be relied upon in a crisis. "To trust in the divine is to trust in failure" is a common refrain preached by Dailan scholars. Thus, it is up to mortals to minimize their "draw" on the gods' provision and power, by doing for themselves what others (the Kaevarians, Trinitarians, or Pantheonites) would wait for the gods to provide.
It is important to note that the Scholars do not doubt the existence of the gods, or their intentions; quite to the contrary, they know they exist, and they know they would seek to pursue their individual aims. In fact, many Scholars argue, it is the fact that gods often vie against one another in pursuit of their own individual goals that uses up a significant amount of the power given to them, leaving less for the benefit of mortalkind.
Game notes
The Dailan Heresy isn't a religion, per se, in that there are no clerics of Dail that seek to advance the cause of a god or the gods as a whole; instead, it is something of an anti-religion, trying to break mortals' dependence on divine power, the way a medical doctor would look to break a patient off of an addictive drug. Bizarrely, clerics of this religion that take the Abandoned domain and receive spells and powers from that. Some even embrace Entropy or the Defier tradition.
Dailan Heretics eschew any divine power, so no characters with any level of paladin or cleric (other than those clerics of the Abandoned, Defier, or Entropy domains) can be a Dailan. Rangers and druids are certainly welcome as Dailans, since they receive their power from Nature, which the Dailans believe to be the power that underlies the entire universe--and possibly the source of the gods' power as well. Any other class is welcome, particularly monks, since their ki powers are entirely "from within". Those who are the true servants of Dail are those who find power apart from the divine--the arcane casters--as they are no longer dependent upon the whims of ancient (and overtaxed) beings for their safety and provenance. Many Mage Schools have long had ties to--and shelter for--Dailan sympathizers.
Those who embraced the Dailan Heresy have, in the past, faced severe retribution from divine organizations; today, the Heresy is less pursued, but religious leaders need very little by way of persuasion to drudge up old laws to harass, block, or even imprison Dailan Heretics. Dailans can be found in any nation in any part of Azgaarnoth, but most operate in secrecy, using simple easily-recognized hand gestures and odd code phrases to recognize one another.