PARTNER cards (パートナーカード pātonā kādo, labeled as "使" (shi), meaning "use", which may be short for "使い手" (tsukaite), meaning "user" or "master") are played to gain additional game effects which work during your or your opponent's Battle Phase. PARTNER cards can only be played by attaching them to an in-play MAMODO card that is listed on the PARTNER card.
Only 1 PARTNER card may be attached to each MAMODO card. PARTNER cards are removed from the Spell Book to be put in play and are sent to the Discard Pile when the MAMODO card they are attached to is sent to the Discard Pile. No duplicate cards featuring the same PARTNER name can be placed on your side of the Gamemat.