Part 1 - Vanishing Point
The basic Animus premise is as follows:
"Attempting to rule the multiverse, mysterious entities sought the power of the Singularity which binds reality together. Their tampering caused it to erupt and scatter its power across time and space. Across the multiverse, various beings were infused with aspects of this power. Now these Entities seek to gather this power for their own avaricious desires. As one of these Entities, you must now gather your forces, claim your power and save..or conquer...Existence."
But who are these entities and what is this Singularity?
After the creation of existence, there remained a linchpin of power that kept the entire multiverse stable. It was called The Singularity, a single point where all aspects of creation emanated from. The Singularity is a conduit of the basic elements: Water, Fire, Earth and Wind, and the natural forces of the multiverse (Gravity, Electromagnetism, Lifeforce and Dark Energy). It keeps the multiverse stable by keeping all universes across different dimensions separate and time flowing in a natural order.
The Vanishing Point
At a place called the Vanishing Point, it was thought safe and beyond the influence of any being. Theoretically, the Vanishing Point is impossible to reach keeping the careful balance of the Singularity undisturbed.
An attempt to extract power from the Singularity causes it to erupt in a massive wave of power throughout all of existence. It is unknown if this was by design or accident but the effects of the Rupture rippled outward and significantly affected everything.
Most mortal beings felt an infusion of power into their soul. Like a metaphysical shot of adrenaline, the very core of their being was greatly enhanced. Normal people became super-powered and beings with power became even stronger. However, this came at a cost. This state of being greatly shortens their lifespan and they will eventually burn out without more infusion of this energy.
Curiously, when a Galvanized being experiences physical death, the energy within them is released and spreads out to other Galvanized beings, giving them an infusion and prolonging their lifespans. This energy became colloquially known as Animus. This Animus can also be forcibly extracted from the Galvanized without killing them but it is a much more difficult and painful process and leaves them dying anyway.
Not everything became Galvanized. Some higher power immortal entities such as divine deities and primordial personifications actually felt a drain on their powers and abilities. Being immortal, this drain wouldn’t eliminate them but left unchecked would make them weak to the point of being essentially obsolete. It is entirely unclear who or what decides what gets Galvanized or Drained.
Although their power was drained, the Entities did gain some new abilities. They could sense Galvanized beings across time and space and could create a temporary tether to them. Once tethered, they could transport the beings to themselves and force them to their will. This is also temporary; like pulling on an elastic, eventually the tethered beings have to be let go and they snap back to their prior location. Being tethered forms a symbiotic relationship. Although drained, the Entities are still very powerful and their power is shared with any Tethered beings. Any Animus gained by the Galvanized is shared back with the Entities which in turn makes both stronger.
This leads to the current state of things with Drained Entities tethering themselves to Galvanized Beings to gain power for themselves. Being Tethered is to the Galvanized benefit giving them more power and survivability as the multiverse unravels.
The Restoration & The Remnant
With the Singularity ruptured, the barriers of different universes are gone and devolving the multiverse into chaos as different realities intersect in unintended ways. Left unchecked, it will continue to unravel until eventually all of existence collapses and ceases.
With the Singularity ruptured, Entities can travel to the Vanishing Point and find a leftover Remnant. They can choose to relinquish some of their Animus into the Remnant in order to restore the Singularity. Likewise, the energy can be drawn from the Remnant to prevent its Restoration. If enough Animus is returned to the Remnant, it will coalesce back into a Singularity and restore the multiverse back to its last state before the Rupture.