The Worldweep is a celestial body in the sky of Golarion, echoing a second moon hanging in the sky at all times of the day and night. It used to be located sitting on the waters of Lake Encarthan, where the Isle of Terror once was, while simultaneously serving as a gateway to the Boneyard.
The Weep is the result of a particularly dangerous alchemical experiment unleashed by the tyrant Mathesis, the creation of which signaled the death of every member of the First Hero's March and shattered the Boneyard, and killed the Goddess Pharasma. Its purpose and effects were multifaceted in that it created a planar barrier between the Universe and the rest of the known planes that only Mathesis could cross, it blocked all divine beings from exerting their will and voice on the Universe while still allowing them to gift their divine magic to the mortals of the Universe, and it increased the flow of souls to the afterlife at a speed that they couldn't be resurrected using most if any known techniques and trapped said souls from leaving the Worldweep in any fashion.
After the Marked adventurers of the Second Hero's March defeated Mathesis, the daughter of Pharasma, Atropos, who had been trapped in the Boneyard during the last thousand years, granted a wish using her divine power to the Marked community, who wished that the Worldweep and consequently the Boneyard that it served as a gateway to, be reinstitued as an afterlife for the souls of the Universe and purify said souls before sending them back to the Material World in a new cycle of reincarnation.
It was stemming from this wish that the Worldweep arose in the Sky and became a Celestial Body in the decades since the wish.
