Spoilers ahead.
As previously written, I also want to explain in more detail how the WEL exchanges energy for effects, beyond simply saying "energy becomes an effect." Before that, some information is needed to understand how this works.
This shared reality has three layers of existence. The first and most important is the Information Layer(IL). Everything stems from it.
Descriptions of the IL are abstract, speculative, and difficult to fully comprehend because it exists at the deepest level of reality itself.
It spreads across all of reality. All possibilities, from beginning to end, are believed to exist within it. The laws of universes originate from it as well, including the WEL.
Next is the Conceptual Layer(CL). This is where beings and structures promoted beyond normal relevance establish their realms, such as the Demonic Realm, the Dragon Kingdom, and partially the Starsea.
The CM(Causality Membrane) stands at the peak of the CL, directly beneath the Underworld, which itself exists just below the IL.
CM does not create the true laws of the universe. It can only restrict or shape them to an extent. The WEL itself is not a creation of CM.
However, CM can act as a Proto-IL for the creation of a new universe or realm, provided enough energy exists to support that creation.
Finally comes the Physical Layer(PL). This layer is the easiest to understand. If the WEL is removed, then the PL is simply another parallel world similar to our own.
Now that the basic structure of the Shared Reality is explained, the nature of the WEL can be discussed.
The WEL is only one possible form of a World Changing Law. Another shared reality, for example "World One," may have magic that stems entirely from a single ruling entity in the same way CM enforces its own restrictions.
What separates the WEL from other systems is that its existence assumes the presence of willful creatures from the very beginning. It rewrites parts of the local Shared Reality's IL so that effects may exist without all intermediate lawful steps being naturally present.
This is what creates Instability.
Now for Instability itself.
Inside this Shared Reality, CM(Lehatot/MainBody) possesses absolute authority over Instability.
For the overwhelming majority of instability inside the Shared Reality, CM performs the stabilization process entirely by itself, making CM a necessary component of the Shared Reality's operation.
For smaller permitted uses of instability involving creatures of the PL or CL, the user only provides a minor amount of work while CM performs above 99% of the actual work. This is intentionally allowed by CM as to give creatures opportunities they otherwise could never get.
Whether this is for better or for worse depends.
However, the only beings truly capable of wielding Instability naturally are Transmigrators, because they are not originally part of the local reality.
CM actively routes their Fate toward situations where they solve instability-related problems until they are eventually promoted beyond relevance, establish a realm, and can no longer interfere with local causality.
CM also lowers the chance of Transmigrators becoming Devils by reducing the severity of many instability side effects or unwanted changes. This is an enormous privilege.
Even so, one thing remains constant:
Transmigrators are repeatedly pushed toward major events. Circumstances continuously gather around them until their Event Mass rises above the threshold of normal relevance.
This affects all Transmigrators equally, including AHIH and TIME.
AHIH, however, differs from ordinary Transmigrators because it is an Avatar. It possesses no true relevance threshold. Even if it establishes a realm, its existence naturally forces it toward the center of important events, giving it immense influence over causality.
This comes at a cost.
Before Transmigration, the lives of Avatars are slowly and subtly molded so they can eventually understand the world they will enter. Most Avatars begin noticing these unnatural "coincidences" at some point before Transmigration.
A single Pre-Transmigration world may produce multiple Avatars. One known case was a world that produced over three thousand Avatars.
A World Zero, however, can only sustain a single Avatar.
As for the part where CM performs nearly all the work itself, its purpose is essentially to fill the missing cogs within reality's machinery.
Transmigrators are one such missing cog.
They are systemically important because they are multipurpose entities: they solve instability directly while also filling roles that reality itself requires in order to maintain continuity.
On simpler notes:
WEL allows:
"Exchange X for Y."
Instability appears when:
Reality lacks a complete lawful pathway between X and Y.
CM performs most of the work required to make that pathway plausible.
For example, an artifact may be connected to a mage somewhere else who unknowingly cast a seemingly unrelated spell.
Examples of the WEL Casting Restrictions placed by CM:
Distance Resistance: The farther the target, the higher the energy cost. Casting close and projecting outward is cheaper. Tools like staffs extend range; some artifacts bypass this entirely.
Causal Resistance: Reality resists effects that deviate from natural laws. Spells aligned with the laws of physics cost less. Repetition or domain authority reduces this resistance over time.
There is also a Global Resistance, causing spells to increase in cost, it can be reduced by having Faith or Authority over a concept, Repeated casting of a specific spell adds to authority over that spell's concept.
Later I will explain Event Mass in more detail, as well as the difference between Fate and Causality.