Kroen, Eternities Collapser

Players may play planeswalker cards they own from outside the game as if they were in their hands.
Whenever a player casts a planeswalker spell, that player exiles half the permanents they control, rounded up.
"And what if all the worlds you could flee to collapsed back to me, and we existed at one point in space, in one moment in time, for all eternity?"