Within the
Jack L. Chalker sagas of the same name, the
Well of Souls is the
computer at the heart of the
Well World which controls the universe. The Well of Souls' access points are at the
equatorial strip, on the borders of the wing-hexes (hexes formed by combining two half-hexes at an outside edge) known as
Avenues. For a few moments at
midnight,
local time, the Well of Souls can be entered from an Avenue by anyone who knows how (like one of the
Markovians, or anyone who has great need.
From inside the Well, a Markovian can manipulate the state of the universe, including shutting down the existing universe and starting a new one. According to Nathan Brazil, this has happened several times in the past.
Given the omnipotence of a Markovian in the Well, every time a Markovian arrives on the Well World, wars are fought to prevent (or assist) them in reaching an Avenue.