Marit Lage Impending

Suspend 20 - {u/b}{u/b}
At the beginning of your upkeep, remove a
number of time counters from Marrit Lage equal
to the number of cards in exile.
Marrit Lage can't be countered.
When Marrit Lage enters the battlefield, exile all
other permenants and all cards from all
opponent's libraries. Then, each player loses life
equal to the number of cards they own in exile.