|Transient card properties|
Cards with rarity are sometimes referred to as mobs along with cards. In the story, the transients depicted in these cards often act as stand-ins for nameless crowd characters, but are occasionally used for recurring nameless transients.
Limit breaking a card requires power stones and spell tokens whose quantity scales with rarity. A full list of cards with for their rarity can be found here.
AR Card Limitation
AR Equipment can only be equipped on cards that match its limitation criteria. Rarity is one of the potential criteria.