Venrah, Sky's Chosen

This spell costs {x} lest to cast, where X is the
number of flying creatures you control.
Creature spells with flying you cast cost {x} less
to cast, where X is Venrah's power
You may cast creature spells with flying as
though they had flash during combat
Whenever Venrah attacks, it gets +X/+0,
where X is the number of flying creatures
you control