Need some Gluum pantheon ideas..

[JusticeZero]

For my Gluumgreen campaign currently, (Epic-6 Pathfinder derived) I am building in something of a Peter Principle based maltheism in all of the gods. I need a few more ideas spitballed at me to flesh out some blank spots on the map, though: a wind-blasted island covered by grass, a hilly island, the insular people of the mountaintops, the scorched and rocky desert, various small, insular towns and hamlets, a deep forest geographically seperated from the Grey-Green's lands where word of its power haven't spread...

According to the Peter Principle, those in an organization rise to the level of their incompetence, the level where their skills and talents are no longer suited for the job they have risen to.

Gods here are localized, personal, and they're all terrible. No clerics here, really; only the gods can grant the ability to invoke magic, and it's not generally in the form of cleric spells.

The way to gain the power of the gods seems to be to be horrifying and terrible, traumatizing many to the point of being that which the dead of the region fear most; the way to keep this power is to convert and protect worshippers who know of their fearsome might—which is of course generally the opposite of terrifying people. As a result, gods are all monstrous and fearsome. They achieved the first part, but now struggle with the second.

I could use some seed ideas for gods to populate the areas near the campaign focus area.

The current local gods include:

The Hags, a hierarchy of Night Hag covens that deal in souls ('dreams'), magic, and portents, protecting human settlements in their area who follow their strict commands and give them the occasional soul;

The Drowned Lady, which resides underwater, and demands tribute of rapists, child abusers, misers, and whomever they can find in case they can't find the guilty to be left to the sea for her to drown, lest she wreak havoc with storms;

Feraal, the Undying Lycanthrope King Reborn, patron of werecreatures and hunting prowess, who tried and failed to colonize the place years ago;

Agon'x, bloodied and dissected god of Pain, Blood, and Surgery, whose worshippers are scarred, pierced, and deal in pain and healing;

The Ruler of the Dead, who needs a better name, and who commands the legions of the undying—demanding respect for the dead and dying, worship, fealty, and corpses from settlements of the living who submit to Their rule;

The Sleeper Below, thought to be the sleeping creator God, prophesied to destroy the world when it awakens, and sealed within a deep, deep mine;

The Grey-Green, enraged nature god of plants and fungi, whose forces destroyed the city of the lycanthropes for their hubris; it rages against humanity still, and converts its disciples into fungal creatures without free will.

Feraal has been trying to essentially rebrand itself as a more acceptable, mainstream faith... With mixed results at best. The Hags long ago settled into the new routine; the party, level two, talked to the local coven last game. The Grey-Green is probably trying to find followers now that it has achieved its slaughter. And so on.

Any ideas off hand?

[Shackled Slayer]

Looking into traditional folklore could be helpful, as well as cultural religious research such as egypt and the mayan empire. The egyptians in particular had allot of local gods akin to what you are describing for your setting.
Another idea is that the gods that form the more predominant powers masquerade under false names in order to steal worship in other areas once they gather up enough power. One reason why they remain local is the many gods decided on a strict territory system, but the loophole is if they use another name it doesn't count. And maybe with the odd century, some gods lose control of this alter ego who has garnered more fame than they have, and manifests into their own entity.
A Trickster god is also a good idea, types like anansi or loki's less murderous moods, the god who isnt exactly powerful but very sly and clever could have a big impact. Perhaps his domains include fortune, destiny, magic and intelligence. They should generally be foolish though, lest they appear too serious. A good trickster god is a lovable buffoon.

Your creator god sounds allot like Azathoth from the cthulhu mythos, as well as the main deity in hinduism. Perhaps a small cult worships the creator, a secretive group that are wary of inviting people into their ranks, eager to awaken the dreaming one.

As for terrains i would suggest either some sort of jungle, or an area with very weird geological structure, like spiraling spires, floating islands or seemingly unnatural, perfect cubes. a place with strange goings on is good too, some place where compasses don't work correctly, or time seems to move differently. Maybe the area has unusual gravity, or lack thereof. Specifically something that the party could use to learn some great secret about the world or use it's strange features to their advantage in a conflict.

Also, are there places where none of the gods can go? Can mortals get there? That kind of area can make it so the players can rid themselves of wrathful or annoying gods that might otherwise pursue them.

[MoiMagnus]

So the gods get their power from being feared by the dead, not by the living, right?
So there is the place for a god of temptation that trade a life of luxury and power against eternal torment after death.

Alternatively, you could go with a god of betrayers, that grant power and opportunity to those who want it the most, but ultimately backstab them by granting power to the ones that will usurp them.

[JusticeZero]

So the gods get their power from being feared by the dead, not by the living, right?
So there is the place for a god of temptation that trade a life of luxury and power against eternal torment after death.

Alternatively, you could go with a god of betrayers, that grant power and opportunity to those who want it the most, but ultimately backstab them by granting power to the ones that will usurp them.

True!
Fear from the dead gets them in the door, but after that they have a system of altars that need worship. Worship requires a different skillset, so it makes for a Peter Principle problem. Gods know about all the altars of all the gods nearby. When they destroyed a Gray-green altar with herbicide, they were described by the Hags as having gained "The Notice of the Gods", who now refer to them by name and call on them as appropriate.

The gods have referred to altars as "Eyes"
In an earlier game. One town had only one altar, to The Hags; that altar was found desecrated and destroyed. Shortly after, the Rogue who had not yet committed to a god met with the God of Pain, who among other things said that that town was "no longer a place". (She converted in that scene, and is now considered clergy.)

They also remarked that their "fingers were numb" where they had sent priests to investigate—the priests missed their check-in and are engaged in hijinks and hullabaloo. The rest of her party was referred to as "Two fingers and a scalpel"; the werecat and alchemist get their power from their respective gods, but the sniper is just a worshipper with good aim.

Then, they met with the God of the Unliving in the last city on their triangle of places of concern, who stated that his/her followers lack geographical barriers between them and the Grey-Green's holdings (fungal/rot God that everyone hates as KOS), so they were very careful to obey the text of the treaty, even though the spirit of the treaty was very obviously being abused. Stolciin warned the party that s/he could not know of any action against his/her neighbor God, told them various information that would be useful to a group of people who intended to go behind his/her back to deal with the infestation, mentioned that s/he didn't have to have a stated reason to reward anyone s/he might choose to, and dismissed them cordially back to the city.

They stopped at the Altar of Feraal in the sewers maintained by the wererats. Some settlements have altars to more than one God; the town is predominantly one faith in all cases so far, with the other altar seeming to have more of an embassy status for a subgroup operating in the area such as the aforementioned wererats.

The werecat had previously been badly hurt by an encounter with spores, and has had indicative dreams of the status of altars near her. This city feels like "A corpse covered in mushrooms trying to open its eyes, with dark dead things in the shadows with glowing eyes, near a small, comfortable throne that watches you kindly".