Arzothra, Demonic Queen

Eminence — If Arzothra is in the command zone
or on the battlefield, other demon spells you cast
get +1/+1.
Whenever Arzothra or another demon enters the battlefield,
choose one —
• Target player draws X cards, where X is half
that demon's mana cost rounded down.
• Deal X damage to any target, where X is half
that demon's mana cost rounded down.