|Egg with an eye|
|Divine Rank||Greater God|
|Portfolio||Motherhood, Fertility, Tyranny|
|Domains||Chaos, Death, Evil, Hatred, Strength|
|Home Plane||Realm of a Million Eyes (Abyss)|
The Great Mother is the matron deity of the Beholder species in the majority of D&D settings. She is believed to have given birth to the entire race. They believe this regardless of who their actual parent is; because of their hugely inflated egos Beholders believe themselves to be born from the Great Mother directly. Each one remembers their birth as a divine moment where the deity wishes the newborn well and sends it on its way-- conveniently forgetting the role of the actual parent, who eats all the Beholder babies they thinks look ugly (which is all of them) and kicking the rest out of their lair because they don't like company.
Beholders believe that the Great Mother knows everything in the multiverse but do not consider her a deity of knowledge, mostly because she does not communicate with her followers in any meaningful way.
The Great Mother has no actual clergy among Beholders. This is because each Beholder believes that they are direct offspring of their god and all other Beholders are malformed heretics who need to be put down. However, the Great Mother does have plenty of followers from non-Beholder races. What's interesting is that although the Great Mother does not speak to her worshippers, she is happy enough to grant power and spells to anyone who prays for it, and will even grant spells on behalf of Clerics who worship individual Beholders, who might not even know that the Great Mother exists.
Ocular Adept is a prestige class for humanoid followers of the Great Mother. To become one, they first have to approach a Beholder and convince it not to eat or disintegrate them. After the hard part is over they enter into a surgical pact, where a Beholder-kin eyeball is implanted in their forehead. This provides them a link to the Great Mother's power and allows them to perform eyebeam attacks to similar to true Beholders. Furthermore, the dying spasms of the creature that the eyeball came from are often taken as divine whispers handed down from the Great Mother herself.
Ocular Adepts have a separate divine spellcasting progression up to level 5 spells, which is in line with that of a Cleric. However, the Great Mother grants more low-level spells than a Cleric and only a few high-level ones. This is because while the Great Mother is "happy" enough to accept followers from non-Beholder races, she prefers to reserve high level spell power for those who really deserve it.
The Great Mother makes her home in the 6th layer of the Abyss called the Realm of a Million Eyes. The layer is an infinite cavern of tunnels and chambers, populated by every kind of Beholder-kin, and the Great Mother is believed to constantly birth new ones. The walls, ceilings and floors of the realm are dotted with eyes, making attempts at concealment nearly impossible considering that you're being watched all of the time. The eyes are believed to be those of the Great Mother herself, meaning that she practically is the layer.
The realm is a horrendously dangerous place for visitors, even the Tanar'ri avoid this layer of their own plane. The realm was apparently first discovered by Illithids, who declared that it must be the source of all corruption and foulness in the multiverse and then attempted to destroy it. It says a lot when even the Mind Flayers think the realm needs wiped out because it's too corrupt.