SBS has said that religion will play a huge role in the story and that it is also one of the more tight lipped aspects of the game. They have also said time and time again that when you see something for the first time they want it to inspire wonder and awe when you see it in game.
There is a number of aspects to the game that on the surface dont seem connected but hopefully after reading this you will begin to see the relationship beyond just another tool of social and tribe guidelines or another way to control the masses in various moral or ethical means.
The first thing to consider is the Soulborn Engine and the Fate Engine as the basis for a driver of religions. The first thing is affinity, story points from infamy or influence, and the fates you could recieve based on those factors along with the day to day decisions you will make or be forced to make. Even if we do not see our actions as good or evil they are still calculated in black or white terms on our affinity wether you follow a faith or not. Our fate will depend on those choices which will carry on throughout our lifetimes on a soul.
The second factor in gameplay terms to consider is the planes they have mentioned or eluded to:
1: The mortal plane (Elyria)
2: The Astral Plane (spirit walking, astral dreaming, etc)
3: The Plane of Time (the Akashic Records)
4: The Celestial Plane (the movement of the stars, comets, etc)
5: The planes of Haven & Karcerion
Each of those will play huge roles with religious implications as pretty much everything beyond the mortal, astral, and Akashic planes are beyond our reach and for the most part we will not see beyond the veil sepperating the mortal and astral planes except through dreams, death, or talents. They even had mentioned spirit guides in the KSV items.
Or on a side note they mentioned in the story Vye just wrote that during celestial alignments such as the Queen's Gaze that the veil between the mortal plane and the astral plane weakens, and in the story the dead can come back and visit us. If you consider all the stars we will name or the existing celestial bodies that will exist all playing a role in different things that can happen or different factions or minions that can appear during such alignments religion will no doubt play a role.
There is also the lore and if you take it as literal rather than lore mann was once a Qin and we were the product of Luna and Ao before we were banished from haven and the cataclysm of the burning that created the planes. At such time Mann and the other lesser Qin mixed with Mann such as Terra to create Ne'ran etc. So there is divinity within our bloodlines and we are cursed by Angelica who created the Akashic Records to see if Mann can be redeemed by keeping a record of all our lifetimes and actions.
But also take a loot at each of the Religions themselves. Each of them talk about or elude to that potential rewards for believing in a particular faith or god within each of the pantheons.
The Virtori:
They believe in the 7 virtues and that the Nerans and Hrothi are the Paladins and Clerics.
The Viceri:
They Believe in the 7 vices and it does not mention their reward for faith, but if the Virtori are the paladins and clerics, then the Viceri are the shadow knights & (?)
The Faithless:
They believe that gods have no influence over them which suggests to me that they actually follow the Qin Mann who was banished and forsook the gods for it. I think that Mann is actually the first Vampire since he was the product of Luna (darkness) and Ao (life).
The Faedin:
The Faedin seem to either follow the Nature elements of the pre burning Qin or the lesser post burning Qin of nature and they are likely druids, rangers, beast masters, werewolves, or animators of plants in some way.
The Qindred:
The Qindred are likely the ones to obtain what people would think of in terms of elemental magic to summon various elementals, to to possess elemental magic at some point.
The Two Fold Queen:
TFQ is the belief in both the creator Angelica or the destructor Luna. In Vye's recent story the Dark affinity during the queen's gaze suggests that her powers are over the spirits and the dead and even possibly liches while at the same time light festi1v1al1s are dedicated to Angelica's light suggesting that good, neutral, or evil spirits can appear during such celestial events as stated above.
Each religion has a duality point to them for followers with a light or dark affinity component and it is likely that most of the faiths will be able to obtain powers or some ascension class based on that.
Combined with the fact that it will be possible to believe in one, multiple, or all faiths at once and get some kind of mix and match benefeit if you are devoted enough to them all at some point.
Consider the talent system to be a shattered fragmented version of the powers the various gods, demi-gods, celestials, or minions can possess but they are all part of the same pool. It might be possible to awaken these abilities through faith, tribal lineage, skill mastery in various skills and levels, spirit level, affinity, and how well you take care of your body through nutrition, etc.