The Bastard's Blade
A D&D Campaign
The Great Mother, progenitor of all Beholders, is said to see all and know all. No secret, no mystery escapes her countless all-seeing eyes.
This is not so. He is left in darkness by her own hubris. In the vast depth of her perceptions, she believes she knows all. There is nothing left for her to learn. Such pride has left her blind.
Eons ago, one of her endless eyes gave birth to a horrid withering beast. Wretched and broken before it could escape malice of its creator, this thing was driven mad before being left to die by the Great Mother.
But even wretched and broken, such a creature is still the offspring of a god. Whether it wandered the planes searching for purpose or what cast into Faerun and left to die by the Great Mother is unknown - even to the all-seeing Great Mother.
In the age of Netheril, when high magic ruled the Forgotten Realms, Lord Spirius brought left blood and suffering in his wake - all in the name of some nameless, unknown power. His horrible atrocities have faded into myth and are recalled only as a byline in a scant few tomes of lore.
None know where Lord Spirius came from, how he rose to power, or how he was defeated. Only his name and that of his sword remain - Caedis, the Bastard's Blade.
Great Mother: Supreme Goddess of Beholders, wants to become truly all knowing, but is held back by her own arrogance.
Spirius: Bastard child of the Great Mother. Fled to Prime Material Plane and took mortal form to hide from his mother. Wanted to become all knowing in the hopes of overthrowing his mother and eventually using the gained knowledge to rule all the cosmos. Slain in the Netheril age, not truly dead - simply lost his mortal form. Has remained hidden in a demi-plane, trying to get back to his sword and its thousands of years of acquired knowledge (see below).
Caedis: The campaign MacGuffin. Crafted by warlords in the service of Spirius' army: the Illuminated Knights. The Knights were skilled magical artisans, and a cabal of their senior members crafted the sword - one from every full blooded PC race from the PHB (Dragonborn, Dwarf, Elf, Gnome, Halfling, Human, Tiefling, etc) to capture a fragment of their knowledge in the sword. Each time someone is slain by the sword, the blade takes their knowledge into itself.
Caedis is an artifact of extraordinary power. Unfortunately, all that knowledge can't be contained by a mortal and if a mortal wields it long enough they eventually go insane from all the info in their mind.
The Illuminated Order: A secret cult maintained by the bloodline of the Illuminated Knights who have remained hidden for thousands of years, searching for Caedis. Have they found the sword yet? Is the sword broken? Venerates and allies with Beholders and Beholder-kin, believing Spirius will return as one of these types of creatures.
Connections to Modules
Lost Mines of Phandelver: Dwarf brothers secretly members of the Illuminated Order? Magical forge used in creation of Caedis? Spectator monster a servant of the cult or spy for the Great Mother? Green Dragon spying on the would-be cultists?
Curse of Strahd: Spirius hidden/trapped in Barovia? Strahd hoping to harness Caedis to break his curse?