Cards can be obtained by summoning them through Nightmare, progressing in the To Do app, etc.
Cards can also be created by combining Card Pieces, which can be obtained through Nightmare, dance battles, etc.
Cards come in seven different attributes:
Pride Greed Envy Wrath Lust Gluttony Sloth
The max rank of a card is dependent alongside its rarity.
Once a card has earned enough experience, it will gain a level and its stats will increase.
The maximum level of a card is dependent on its rarity.
The maximum level of a card can be increased by unlocking a Rank Up Space in Devil's Tree.
*When your card has reached its maximum level, you can unlock the maximum level cap to increase the maximum level of the card.
Demon Cards and Memory Cards have skills which can activate during dance battles.
These skills can increase your team's stats and decrease the enemy team's stats, among other effects.
Skill effects vary by card. They can be viewed by tapping and holding down a card.
*Card skills have a maximum level of 10.