Looking for an extraplanar BBEG

[Nidgit]

I've inherited a new campaign from the previous DM and I want to flesh out the unspecified BBEG so I have a better sense of where this is all going eventually.

The thrust of the story is that the BBEG has been impersonating a god and has tricked the world into accidentally cutting off the source of magic (need to find a way to mechanically implement this too). The BBEG has been siphoning off this magic to supercharge themselves and should be in a position to either keep growing stronger while the world grows weaker or unleash their built-up might if the seal is broken.

I'm not sure what kind of creature could fit the bill though. I'm considering potentially a Nagpa, but those are usually more puppet master than intimidating threat in their own right. The party is a chaotic, fun-loving bunch so I don't want to lean too hard into cosmic horror either. The requirements I mostly want to fulfill are:

1.) A powerful extraplanar entity
2.) Capable of challenging 5-7 Level ~17 PCs (somewhat negotiable, I can scale up or down)
3.) Capable of impersonating a god and tricking high-level NPCs
4.) Can have thematic minions both in the final confrontation and as foreshadowing
5.) Cool

[nickl_2000]

Sounds like something that the Illithid would be doing to me.

An Elder Brain could easily appear to be a deity to sleeping (N)PCs with their psychic link. Plus those crazy illithid are always up to something like this. As for syphoning off magic, I would have it be part of the Elder Brain's lair, there is an artifact in there that grants the brain more abilities or can be broken to give a gigantic burst ability.


Easily have them run into brainwahsed minions, Gith working against them, etc

[gloryblaze]

Impersonating a god and being a chaotic, tricksy jerkwad is kind of the MO of the demon lord Fraz-Ur'bluu (stats can be found in Out of the Abyss or Mordenkainen's Tome of Foes)

[Veldrenor]

A demonlord or archdevil could work. They're extremely powerful, some can change their appearance to be more appealing or are god-like as-is, and they're ambitious and power-hungry enough that they'd be keen on implementing such a plan.

Or, in the opposite direction, it could be an angel. Maybe they're doing all this to punish the world for some great sin in the past. Maybe they think they could do a better job than the deity they serve and this is their attempt at apotheosis. Maybe they were cast out (either rightfully or not) and this is an act of vengeance.

[1Pirate]

A fallen Empyrean ticks most of your boxes.

[J-H]

This sounds like Vecna, pre-ascension? Or maybe a leftover contingency plan?

It depends on whether or not you like the 5e "Lichdom requires continuing to eats souls" fluff.

[Nidgit]

This sounds like Vecna, pre-ascension? Or maybe a leftover contingency plan?

It depends on whether or not you like the 5e "Lichdom requires continuing to eats souls" fluff.
It probably can't be Vecna given that some version of his Hand is an artifact that party is looking for right now. Though maybe...

[KorvinStarmast]

I've inherited a new campaign from the previous DM and I want to flesh out the unspecified BBEG so I have a better sense of where this is all going eventually.

The thrust of the story is that the BBEG has been impersonating a god and has tricked the world into accidentally cutting off the source of magic (need to find a way to mechanically implement this too). The BBEG has been siphoning off this magic to supercharge themselves and should be in a position to either keep growing stronger while the world grows weaker or unleash their built-up might if the seal is broken.

I'm not sure what kind of creature could fit the bill though. I'm considering potentially a Nagpa, but those are usually more puppet master than intimidating threat in their own right. The party is a chaotic, fun-loving bunch so I don't want to lean too hard into cosmic horror either. The requirements I mostly want to fulfill are:

1.) A powerful extraplanar entity
2.) Capable of challenging 5-7 Level ~17 PCs (somewhat negotiable, I can scale up or down)
3.) Capable of impersonating a god and tricking high-level NPCs
4.) Can have thematic minions both in the final confrontation and as foreshadowing
5.) Cool
I suggest an Ancient void Dragon, which isn't from any core books, but it is from IIRC tome of beasts and can be found at the 5esrd site. CR 24.
Use star spawn as minions. (Mords or Volo's, can't recall at the moment)
Can't get at that web site at the moment, but I am pretty sure that like all other ancient dragons it can change shape into other critters. So it can fool PCs.

I am about to confront my party with an adult void dragon (CR 14) whose minions are from a variety of planes (they already took out some of the shadar kai, and the last ones will be star spawn).

[kazaryu]

I've inherited a new campaign from the previous DM and I want to flesh out the unspecified BBEG so I have a better sense of where this is all going eventually.

The thrust of the story is that the BBEG has been impersonating a god and has tricked the world into accidentally cutting off the source of magic (need to find a way to mechanically implement this too). The BBEG has been siphoning off this magic to supercharge themselves and should be in a position to either keep growing stronger while the world grows weaker or unleash their built-up might if the seal is broken.

I'm not sure what kind of creature could fit the bill though. I'm considering potentially a Nagpa, but those are usually more puppet master than intimidating threat in their own right. The party is a chaotic, fun-loving bunch so I don't want to lean too hard into cosmic horror either. The requirements I mostly want to fulfill are:

1.) A powerful extraplanar entity
2.) Capable of challenging 5-7 Level ~17 PCs (somewhat negotiable, I can scale up or down)
3.) Capable of impersonating a god and tricking high-level NPCs
4.) Can have thematic minions both in the final confrontation and as foreshadowing
5.) Cool

i mean, to me it sounds like really you want to focus on 1 and 5. first find a powerful extraplanar entity that you find cool. the rest is just leg work.

2. as you point out, that is just a matter of scale.
3. any creature with access to 5th level magic or higher is capable of impersonating a god. Dream is extremely useful in this. but really just...5th level magic is where **** starts to go wild. as far as fooling PC's. Glibness and magic aura are both great for that.
4. any high tier monster can have minions, especially one thats masquerading as a god.

[Naanomi]

Baernoloth?

Or any of the beings that just don't like Gods... Aboleth, Ethergaunt, etc...

Or someone whose motivations are incomprehensible? A cabal of spellweavers?

[J-H]

It probably can't be Vecna given that some version of his Hand is an artifact that party is looking for right now. Though maybe...

Head of Vecna!
Head of Vecna!
Head of Vecna!

[da newt]

Maybe an Atropal might be a good starting point - just tweak the life drain aspects to magic ... like the one in ToA

[Naanomi]

What was the 3e thing that could turn off an entire plane's magic... Pandorym?

[PattThe]

Any Yugoloth, and their planar portal hopping ways.

[Khrysaes]

Lich queen of the githyanki? Or that one devil /red dragon?

Just checked the dragon is her consort.

She eats souls and wants to ascend to divinity, so it fits her.

[Mastikator]

Radiant Idol from Eberron checks all the boxes. CR 11, has an ability called "Aura of False Divinity" that acts as a charm aura.

Part of their description: "One sin led to their fall: the desire to be worshiped by mortals."