A guy uses a "key" to open a portal to the forgotten realm of Deadlight.
This drains the "key" and inside Deadlight there is no "essential energy" to recharge the key to leave.
The realm is "devoid of life and energy", yet can see lighting, there is wind, there is light, all forms of energy, unless energy specifically means MAGICKA.
SO HEAR ME OUT, what if the "key" was abolisher, and what if "energy" actually refers to MAGICKA. That would mean the place Ithelia is exiled to is not our irl world, but the realm of Deadlight!
According to the lore, Mehrunes Degoth chased a forgotten prince here and destroyed the realm, this must be a reference to Ithelia... And if Ithelia is sent back there, imagine how she might feel with the recollection that they didn't just erase her from history, but did all of this to her.
I also wonder if Meridia may be involved somehow, given in her realm at the end of the base game Main questline, if you turn around you, you see a massive glowing light ghostly-green in the distance that looks like the color of Deadlight. And the name is literally Dead-light, with Meridia being associated with the "energy of living things", and being themed around light.
What if Meridia was shattered into two beings, with Ithelia being a fragment of her?.. So many thoughts, I really hope we learn more about Deadlight soon and get a follow-up to Ithelia's story.