Highborn of Grimm

As an additional cost to cast this spell, sacrifice a creature.
Royalty - When Highborn of Grimm enters the battlefield, target creature gets -X/-X, where X is the number of creatures with royalty you control.
While there are many different kingdoms in Grimm
with many different royal families ruling them, they
are all united by two brothers only known by the
name The Brothers Grimm.