The Inquisitor

Eminence—If The Inquisitor is in the command
zone or on the battlefield, you may tap a Demon creature for each non-Demon creature you
control. That creature doesn't untap during its controller's next untap step.
The Inquisitor's power is equal to the number of
non-Demon creatures you control, and its
toughness is equal to one plus that number.
Lifelink