Zhou Yu, Wu Tactician

Eminence- Noncreature spells you cast with
converted mana cost less than Zhou Yu's
casting cost cannot be countered.
Whenever you cast a spell with converted
mana cost less than Zhou Yu's recent casting
cost, you may pay {x}, where {x} is the
difference between the two, to copy the spell
{x} times. Zhou Yu must be on the battlefield
to trigger this.