Sword of GreySkull
The goal of the Quest of the Sword of Power is to acquire the other half of the sword hidden inside Castle Greyskull in order to obtain the sword’s total power. Legend adds that “the magic fires, created by ancient scientists and sorcerers, will blaze again” once the two halves are joined. The specific purpose of the quest is also rumored in ancient myth: the Power Sword can be used to open a hole in the dimensional wall in order to bring reinforcements from another dimension, which would allow the master of the sword to conquer Golarion’s dimension. Once the two halves of the Power Sword are joined, It’s wielder would able to use the sword to open Castle Greyskull’s Jaw-Bridge when inserted into an enchanted lock.
An ancient epic poem, The King of Castle Greyskull, reveals where the two halves have been hidden: one at Golarion’s “highest point”, the other beneath its “hardest rock.” Whoever finds them can claim the throne of Castle Grayskull and the “secrets of the universe”.
Castle Grayskull is a legendary/mythical location situated in a barren wilderness. It serves as home to a powerful Sorceress, and a place of refuge for The Champion of the Sword and all those considered his Allies. Its origins are unknown except for the fact that it was constructed to protect an unspecified source of power from those who would misuse it. It is a frequent target for the forces of evil.
Although it is mostly viewed from the outside, there are a few notable internal locations contained within the legends: the Throne Room; the Hall of the Champion; the Travel Corridor Chamber; a laboratory; a room used by the Sorceress for studying and practicing spells; and, the Sorceress’ bedroom (and all that THAT entails). In the epic Song of the Eternal Champion, a vassal of the Champion of the Sword named Koldar also comes across the chamber that houses the Secrets of Castle Greyskull. It is a room with two doors, between which sits the Guardian, one of which houses the secrets, the other only destruction.
The castle is surrounded by a bottomless abyss, which serves as a moat, and a Jawbridge (a drawbridge formed by the lower jaw of the castle’s “mouth”) is used to come across it. When the Sword of Power transforms it’s wielder into The Champion, bolts of divine power shoot up from the abyss towards the sword. In the same bardic song it is revealed that the abyss actually leads to the center of Golarion.
In the surviving legends, there are stories of a number of magical doors inside the castle, most of them in the Travel Corridor Chamber, that serve as portals to various locations on Golarion, including Snake Mountain, and at least one that leads to Etheria, thought to be another of the worlds orbiting Golarion’s sun.