The Source is a cosmic force that permeates the entire multiverse. It comes in many forms, including the four physical forces, magic, mad science , and narrative causality. On Earth, it is known as the Tao, the Logos, or dharma. With enough power, the Source can be used to bring new large-scale universes into existence. Attempts to study it using scientific methods are difficult as it is conscious itself and often responds to one’s personal beliefs.
Many beings have discovered that by accessing the Source, they develop new powers. Exactly how these powers manifest depends on their beliefs and level of raw mental power. Wizards gain the ability to cast magic spells, mad scientists are able to develop super-advanced technology, and martial artists develop enhanced strength and speed. Those who are sufficiently connected to the Source can even use it to escape the cycle of reincarnation and ascend to the Upper Planes.
The amount of Source energy in the multiverse is actually limited and would eventually be drained within trillions of years. This is because a Source wall surrounds each universe that so that outside Source energy would not interfere with Eru’s creations. However, energy can travel from one plane of existence to another through interdimensional portals. Since the total set of all universes is a closed system, the multiverse is subject to the laws of entropy, which not even the Elder Gods or Archdevils can reverse.