The War in Heaven

As The War in Heaven enters the battlefield,
exile all non-land permanents for as long as The
War in Heaven remains on the battlefield, then
create an X/X white Archangel token with flying,
where X is the amount of non-land permanents
exiled.
"With the promise of Free Will at stake, heaven went
to war. And although they won, a third of the host of
heaven was lost."