I'm not sure if this has been brought up before, but in the Monster Manual, one of the creatures that really caught my eye was the Kuo-Toa. In the description, it talks about how if enough of them believe that a god is real, the energy of their collective subconcious can cause that god to turn into a physical entity. I was thinking that would be really cool to use for something, perhaps my party stumbles upon a group of them worshipping a huge wickermanesque idol they set ablaze that comes to life, or they get inspiration from a beautiful woman they kidnap and lock away, and their idea of her turns into something twisted and warped, and manifests into a monster. Does anyone have suggestions for what the stats would be for such a thing? Perhaps I could make it invulnerable, and it only disappears when all the Kuo-Toa have been taken care of? And secondly, it also states that Kuo-toa that encounter an aboleth usually begin to worship it as a god as well. Would you give a boon to an aboleth being worshipped as a god? Perhaps advantage on everything until the Kuo-Toa are delt with?
check out the DMG, they have boons and charms as alternate treasure. youcould use that.
i would say damage resistances and immunities.or perhaps just reskin a demon or something as long as it thematically fits.
for instance a black pudding sparks their insane interest as a manifestation of entropy, give it spellcasting abilites like a cleric of death.
a 3rd party publisher had a concept for 'small gods' the number of followers vs number of priests able to cast spells was central to issue. how long have they worshipped it? maybe it just gained sentience so far.
I recently created an avatar of Blibdoolpoolp you may find useful
http://community.wizards.com/forum/dungeon-master-help/threads/4224266
I would second the "reskin a demon" idea (slaadi also work well), maybe add a couple levels of warlock (GOO) and/or look at some of the legendary stuff (1 use of legendary resistance per 10 followers in its lair). I would also think about giving it lair actions (using the black dragon's lair actions).
For the aboleth, I would let it cast the underdark land druid's circle spells (the 3rd level while it has 10 or more kou-toa followers, 5th while it has 20 or more, etc.) or give it a couple of levels of the mystic class from the recent UA article while it has kuo-toa in its lair.
BLIPDOOLPOOLP! The god that's as much fun to say as they are to pray!
Why is everyone speaking Otyugh all of a sudden?
Thank you guys! Those are all great ideas, I might try to incoporate them all into different things. Haha I do love the name as well, when I told my party about it they wouldn't stop laughing. But he's beautiful Byaku!
You could re-skin an Adult Dragon, or anything else whose CR is about what you want in a solo monster.
I'd also add something psionic-esque to it, because it gains its power from the kua-toa's belief in it. It really wants more worshippers.
Dragon Frightful Presence field of effect + Suggestion spell mechanics = ??? (more followers, it hopes)