The Deadlands Chronicle
The fundamental energy that comprises all things. In its pure form, mana is the life energy of the world, and it suffuses everything within it. Originally, mana flowed freely between all things via the conduits and leylines comprising the Web of Life, but following the Profound Disjunction and the destruction of the Web, it now no longer flows.
It is possible to extract mana from the land and manipulate it to achieve supernatural effects. Manipulating mana in this way is known as magic, and its practice enabled mankind to build the world-spanning empire of Kalesh-Tar, command the elements, and even open gateways to other planes of existence. However, because mana no longer flows through the land after the Profound Disjunction, the art of magic has been rendered impotent.