The Agera take on religion remains one of simplicity, a polytheistic belief with overtones of animism. The general Agera view of the spiritual world (not including the extreme multitudes of Parakonian gods and the Tsartian addition of ancestor spirits to the mix) is this- the world is full of gods; some of them are great, while others are small. Agera tend to think of anything which they percieve as supernatural as a "god" of some sort, and tend to refer to natural forces in terms of reverence, similar to practitioners of shamanism. What gods, precisely, an Agera believes in depends on the location and the person; most Agera tend to believe that one god is superior to all others, and even though other gods may exist than their chosen deity, said others are not worthy of reverence (this can be seen in the shift of the Mysians from worshipping a great multitude of gods simultaneously into worshipping the Phoenix almost exclusively, relegating the other gods to the status of helpers; note also the combination of the original Carmanian gods into "aspects" of Amalias).
Most Agera, beyond believing that their god (or gods) is the greatest above all others, tend to be rather tolerant of other (religious) viewpoints (though it is not uncommon to hear Mysians and Carmanians trade insults of "Goat-lover!" and "Chicken-worshipper!"). There is, however, one viewpoint to which almost all Agera respond with incredible horror and rage, that of the Atheists, a group who are reviled above all others as murderers, rapists, inverts, madmen, freaks, fools, blood-drinkers, cowards, destroyers, and generally as any other insult which can be thrown at them. The common belief of the Agera is that an Atheist is somebody who has sold his heart to a demon, and who intends to devour the souls of everyone around them, while a more nuanced view regards them as abominable dangers to the social order who threaten the collapse of Agera civilization.
Though many Magi would have one believe that the horrible Atheists are everywhere, waiting on every corner to leap out and strangle a child, poised behind every open door to cut a throat, there are actually very few of these folk in Ageratos, for reasons which must be obvious. In these days, Atheists have mostly been wiped out in religious pogroms- one of the most notable of these being the Burning of the Godless which took place in the Three Kingdoms roughly 50 years ago, in which over 400 communities of Atheists were hunted down and brutally murdered. Those Atheists which still exist live in tiny, isolated communities, generally in otherwise-empty wilderlands, and rarely seek outsiders.
(For reference, the Ageran concept of "Atheist" is slightly different than our own- rather than one who does not believe in the supernatural, an Ageratos Atheist is one who denies the divinity of gods, and regards them simply as another, more powerful group of beings of the Outer World who happen to share the world with mortals)