Well we know through information and events in terms of the Blade of the Black Empire that in actual fact the Light and the Void are connected and essentially the Void is actually Light which has changed to instead absorb all light…so it’s the place of no light.
This definitely could be a case that knowing that Light actually does eventually succumb to the madness and become void so become the exact opposite of everything we are told the light is about.
The void can be returned to the light through the absorption of a lot of blood (Life Essence) so actually causing death to return to the light…
Think about that the Infinite Void is just using the realms of the dead as a means to an end of returning itself back to the light. Only to once again have some of it succumb to the Void and repeat this all over again… and again drawing in any thing that has Life essences to return itself back to the light.
So if not Elune could it have been one of the Naaru or other beings of light who in the process of falling to the void played a part in the events that took place.
I understand that Elune is many things but we also see that there have been visions and even scenes in other realms and planes that show Elune in very different states and even one from memory that actually show’s Elune with what appears to be shadowy old god like tentacles as coming from her…
Shadowy and old god makes you think N’Zoth and we know that N’Zoth was able to somehow be in various different places in some form or another even if it was just his voice… So was he really trapped as we thought and did we really actually release him or was this something else once again?
IMHO I think we are going to see something that essentially means that N’Zoth has been twisting Elune and actually corrupting her for some grand scheme.
Could this be the reason for the destruction of the World Tree and the beacon of Life?
That all being said I honestly think it’s far easier to understand the motives and actions Sylvanus takes… What was the one force that effects changes that makes changes unfolding events to create the impossible… Oh yeah it’s LIGHT…
Was the actions of Sylvanus and the burning of the World Tree a way for her to ensure she weakens the lights reach and the abilities of the Light Gods to change something and prevent her current course of action.
So really it was a method to ensure that the ability of Light couldn’t be utilized to disrupt the steps of death and prevent her for completing what she has been trying to do all along.