So, with the final confirmation that Anduin is in fact going to be Arthas 2.0 it begs a question about a whisper that we've had on the back of our minds for a while. What was this pact? What are the details, what is the trade, what exactly does this mean?
More importantly... what if this pact was fulfilled by the Light when Anduin was delivered to the Jailer?
We always thought that "the enemy of all" was talking about the cosmic force of death that threatened to consume us all. "Six seats at the high table, six mouths that hunger. One will consume all others" was the exact quote and for the longest time the assumption was that each of these seats was suppose to be referencing each cosmic force in this multi-dimensional power struggle. The problem is that the realm of death is actually really balanced when it's working like it's suppose to and from what we can tell the realms of death aren't interested in consuming all others. Except the Jailer. Matter of fact, the only way the Jailer can actually "break the machine of death" is by making sure there is no difference between life and death. The only way to do that is by killing all forms of life and only allowing one state to exist. If everyone is dead there can be no life, if death consumes all others there will be no more machine of death because it will be the only thing that exists.
Back to the seats at the table though. What if this is more focused and less broad? What if they're talking about six traitors, one from each of the planes? We know Sargeras is already a traitor to the realm of Order and the Jailer to Death. What if there was a conspiracy between the traitor from the light and the Jailer? A deal to deliver Anduin, a prolific agent of the light by any standard, directly into the hands of the Jailer. Anduin's new form is being described as a weapon and from what we can tell the Jailer has had a very weird obsession with him that makes little sense except for the singular fact that he's so well imbued with the light. What if this new weapon can wield both the power of the light and death? It's the only reason I can spot for such the weird obsession with him. The jailer clearly isn't interested in the Alliance or Horde outside of killing both of them so his political position is meaningless, he's not a particularly well renowned warrior, mage, or mind. The only value Anduin can possibly have to the Jailer is that he's so connected to the light.
With him gone and Turalyon firmly on the throne of Stormwind, the light would likely be in a very advantageous position to bring itself to Azeroth. The majority of the Alliance would likely back the light, we know Yrel is running around out there forcing people into service of the light. The Horde might be a problem but with the majority of the Alliance, the forces of the Army of the Light, and the forces forced into service on Draenor... who would be able to stand against the light?
Maybe Shadowlands is truly the reverse BfA where the final patch of the expansion is incursion of the Light to contract the 8.3 incursion of the Void?
Sorry for the tinfoil hat post.