Mathesis, also known by her title "The Alchemist", was a human woman in the age of Lost Omens who used her vast and incredible knowledge and skills with the art of alchemy to do many great and terrible acts.
(Part of Entry of her personal history)
She defeated the lich Tar-Baphon at the Isle of Terror and used his Isle of Terror as the staging ground for her war against the rest of the World, making many credible threats suggesting she may usher the end. This prompted the various nations and peoples of the world to send a Hero's March consisting of various of the most notable Heroes and Villains of the age to put aside their differences and form what was known as the First Hero's March in an effort to storm the island and stop whatever plans Mathesis had put in place.
Upon a party of heroes utilizing the sewer pathways to sneak into her Control Room, Mathesis activated her ultimate project, the World Weep, which instantly killed every member of the First Hero's March, simultaneously as a dark orb consumed the entirety of the Isle of Terror. The World Weep additionally destroyed the Boneyard and the goddess Pharasma, and created a barrier between the Universe and all the other Planes of the Great Beyond.
After this event, Mathesis proceeded to rain down Alchemical Weapons upon every major settlement and structure of the planet Golarion and reduce the entirety of the planet to living in secluded hamlets for the next thousand years, a new age called The Age of Collapse. If a particular settlement or other structure rose to an arbitrary metric of success in this age, Mathesis would release a new alchemical experiment to destroy it, usually in its entirety. It is speculated that in the thousand years, Mathesis was trapping all deceased souls of the denizens of the world in her World Weep to extend her lifespan and study the nature of Life.
Upon an experiment bringing the Fletchling Adrianna across the planar boundaries, Adrianna, along with a few other denizens of The Age of Collapse, founded the Harbor of Hearts adventure guild and put in place measures that prevented Mathesis from striking it down, along with a few key buildings in the settlements of Moonlit Village and Snowmelt Harbor.
This Harbor of Hearts cultivated multiple hero's that grew in power to match their ancestors of the First Hero's March, and eventually launched an attack on the World Weep called The Second Hero's March. A band of heroes broke through the event horizon of the World Weep, and struck down Mathesis right before her apotheosis into a godlike being who encapsulated pure, unfiltered vitality or positive energy.
Her death, and subsequent passing of the reins of the afterlife to the Goddess Atropos marked the end of The Age of Collapse, and the start of The Age of Renewal.
