[Chaos]

Karaten Guard Commander: This is fine.

"The Box": This, on the other hand, sounds like an extremely roundabout method when Karaten's preferred response to troublesome Liches is to just teleport them directly into the Void, which bypasses any sort of Phylactery nonsense. 

I also find the idea of a 'inescapable plane between Void and reality' to be dubious. Additionally, even if such a plane existed, I would have to question if the forerunners on portals and teleportation, the Majistras, would put in effort for this contraption compared to 'toss them into the plane of oblivion and call it a day'.

As it stands, this idea needs some more clarification-- namely on why this would be used instead of 'toss 'em into the Void'.