One Tree, Many Branches: Multiversal Laws

Nestled somewhere in between the fabric of spacetime, there exists infinite but distinct dimensions of reality that all trace their origins back to a single point.

These dimensions are not separate planes of existence like the Feywild or the Abyss. Rather, they are branches in reality that break off from one another at any given moment where two or more outcomes are possible. Each branch becomes its own concrete reality that can then spawn more fractals exponentially and into infinity.

If viewed as a simple timeline, branches whose point of divergence are close in proximity will usually closely resemble one another, with neighboring branches being all but indistinguishable from one another, while those with more distant breaking points would be almost unrecognizable to each other.

Also unlike the various Planes of Existence that can be freely travelled between by those with enough magical aptitude, there are only a handful of spells that allow their casters to walk between dimensions. Some particularly powerful entities are capable of perceiving or even communicating with their multiversal variants, and are thus able to more easily blur the lines between them. However, this is a vanishingly rare exception, and not the rule.