"Attribute" (属性Zokusei) is a property to categorize the cards by a specific group. Each card in the game has its own attribute, and some may have from two up to five different attributes. In card text, attributes appear within "《》". Attributes also can be divided by traits. That is, a group of attributes that share the same word on them. Support cards usually affect attributes, allowing decks to be built based around a specific attribute. Some archetypes can also have archetypes within them.
Every World has different attributes from which decks can be built, those attributes often have their own mechanics that usually follow the general theme of the World they belong to with some unique variations.
Some special flags list a specific attribute and allow the player to use any card from it regardless of the World, but can only use cards from the listed attribute.