Zagras, Thief of Heartbeats

If a spell has a cost reduction based on the number of creatures in your party, no player may attempt to change that number after you begin to cast the spell but before you pay the cost.

If a creature has more than one party creature type, and there are multiple ways to count that creature that could result in a different number of creatures in your party, the highest such number is used. For example, if you control a Cleric and a Cleric Wizard, the number of creatures in your party is two. You can't choose to have it be just one by counting the Cleric Wizard first as a Cleric.

An ability referring to the number of creatures in your party gets a number from zero to four. Such abilities never ask which creatures are in your party, and you never have to designate specific creatures as being in your party. You can't choose to exclude creatures from this count to lower the number.