Certain cards grant additional effects for only having cards from 1 civilization in your mana zone. These include:
While these cards support only playing one kind of civilization, cards with 2 or more civilizations can still be played in small amounts. However, they should still share a civilization with the cards listed above in order to still allow their abilities. A card such as Piercing Judgment in your mana zone would still allow Prism-Blade Enforcer's ability to be active.
|Civilizations of the Creature World|
How to Play