Regnum Angelica is played with one player having the white deck to represent the archangels of Gabriel, and the other the black deck to represent Beelzebub and his army of fallen angels. Each deck consists of three types of cards: Angels, which are your main combat units; Angelic Scripts, written in the ancient celestial alphabet (Malachim) and granting the angels special abilities to assist them in infiltrating the enemy realm; and Pillars, which call up the elements of earth, fire, or water to protect them from enemy attacks.
Each army has a power meter which is charged when either side's angels visit earth. The power meter must be carefully managed if you hope to crush your opponent as your power meter determines your movement and your ability to execute the Malachim. If too many Angelic scripts are played, then your mobility on the board suffers; if, on the other hand, you use your power for movement, then your ability to harness the powers of the angelic scripts wanes.