Hello everyone, so i've created a new idea for one of my campaign main villains, this is a new creature with new lore so i would appriciate the feedback/improvment.

the creature is called the "Faithless Host" and the idea is that it is a twist on the whole "wall of the faithless" dilemma(which has been overdone already): the former Villain modified a Mythallar to be able to absorb and contain an enormus amount of souls (the catch is that the souls have to go into the Mythallar willingly or else it wont be able to contain thousands of unwilling souls) so the villain lead a disposable army(mostly consturct, undead and demon raiders) to the wall of the faithless and offered any soul that was not already completely absorbed into the wall a chance to escape into the Mythallar, which alot of them did willingly. after that he returned to the material plane and with the help of Velsharoon, the necromancer deity, he created the Faithless Host, an amalgamation of all the faithless souls from the wall into a massive spectral undead creature(a demilich and several necromancers in the service of Velsharoon have also been sacrificed in the creation ritual).

Now, the faithless host is powerful(CR 24-27),however his power is not the real danger, its his area effect that is the real problem. because its made up of thousands of souls who all share one thing: they are all faithless and angry, it has a sort of psychic effect for miles around its location that causes people to literally lose their faith in whatever god they belive in. this does not affect everyone, only people whos faith have been shaken for one reason or another and once a person is "infected" with the faithless curse the faithless host will detach souls from itself to create minions called "dark shepards" whos job is to offer faithless a chance to join the faithless host(he cannot force anyone to join him, especially those that belive in a god) reminding them what await the faithless in the afterlife.

Goals: The Faithless Host knows its not going to win, once the gods realize what it can do they will send their agents to destroy him. the host long term plan is to cause as much havoc as possible, specificly for the gods because it belives that the punishment it endured as a faithless is too severe, it wants the gods to understand the danger the faithless pose and that it only exist because of the way faithless are dealt with in the afterlife(the host must have something that binds all the souls it has inside him together or it will simply break apart).

the faithless host will also have several powerful enemies(some of them might become the players allies): Asmodeus, will send his agents to collect the thousands of faithless souls which for him is a true treasure. Kelemvor, he will see the host as an abomination and will send his agents to retrive the souls stolen from his city. Velsharoon, when he aided in the creation of the faithless host he was lead to belive by the former villain that he would have a mesure of control over the creature but he was tricked and now he wants to either assert control over the host or see it destoryed.

thank you for your time, let me know what you think and i would appriciate any suggetion for improvments.

I like the idea of this villain.
It knows it's going to lose so it'll be more desperate and willing to wreak as much damage as possible.
Hell you can make it ironic that more people will actually begin to worship IT! Have it have bystanders, people who have been wronged by the gods or feel like they have. 
Hell it might get allies from lesser demons or gods if you fancy, trying to manipulate it but it could manipulate them in turn. 

Maybe even have heroes that went to stop it and instead fell prey to losing their faith and now have joined their forces.

Quote from Gorvar >>

I like the idea of this villain.
It knows it's going to lose so it'll be more desperate and willing to wreak as much damage as possible.
Hell you can make it ironic that more people will actually begin to worship IT! Have it have bystanders, people who have been wronged by the gods or feel like they have. 
Hell it might get allies from lesser demons or gods if you fancy, trying to manipulate it but it could manipulate them in turn. 

 im trying to figure out what kind of being(faction, lesser demon or others) hates the gods/would profit from their destruction and would join it, maybe the Abeloth or demons of the abyss? im not a master of forgotten realm lore so im very unsure.

Quote from HeroZero >>

Maybe even have heroes that went to stop it and instead fell prey to losing their faith and now have joined their forces.

 thats a good idea i will try it out :) i also thought to make a mechanic that the closer the player get to the faithless host the more they will  have to make a sort of "faith check" that will become higher and higher the more they come near the host.

Aboleths seem like a great villain to fulfill the one you have in mind. Aboleths were the first beings on Toril (known as Abeir-Toril back then). They enslaved all of the first races of the world, and when the Gods came and crushed the Aboleth empire, the Aboleths never forgot, they remember everything their parents and ancestors knew. They are also fairly immortal, when they die they reform in the Elemental Plane of Water, so that would be useful if you want it to be a recurring villain. 

Quote from LeviRocks >>

Aboleths seem like a great villain to fulfill the one you have in mind. Aboleths were the first beings on Toril (known as Abeir-Toril back then). They enslaved all of the first races of the world, and when the Gods came and crushed the Aboleth empire, the Aboleths never forgot, they remember everything their parents and ancestors knew. They are also fairly immortal, when they die they reform in the Elemental Plane of Water, so that would be useful if you want it to be a recurring villain. 

 nice! so they would willingly join or at least send someone on their behalf to aide the Host since it seems to represent exactly what they are looking for.

do you have any idea what would be the best place on Faerun for the host to go to(or send its agents)? i am looking for a land that is very religious maybe places that have a strong presence of the Church of Tyr or the Order of the Gauntlet.

Some place near the ocean, or a tunnel to the underdark, both places where Aboleths live. I'd recommend Neverwinter, it has quite a few temples. About 10 miles South East of it, there's the paladin/war priest stronghold Helm's Hold. It is also on the Sword Coast, so close to the ocean. Helm is the god of order, and law. 

Does this work?

I think that is a good setting, somewhere nearby perhaps, like the marsh of dead men could be the initial epicenter.

Quote from LeviRocks >>

Some place near the ocean, or a tunnel to the underdark, both places where Aboleths live. I'd recommend Neverwinter, it has quite a few temples. About 10 miles South East of it, there's the paladin/war priest stronghold Helm's Hold. It is also on the Sword Coast, so close to the ocean. Helm is the god of order, and law. 

Does this work?

 yep its an excellent idea, thanks :)