Color (色 Iro) is a characteristic possessed by a card. A card may have one of the five possible color:
In addition, there is also exist colorless cards, which is often represented with a grey circle or generic Ignition Icon.
The color of a card is indicated by the Color Icon, which is located in the upper left side of the card (for cards with old frame) or the upper right corner of the card (for cards with new frame), and is used to determine how the card's Cost is paid and what kind of Resource it provides.
Storywise, a card's color also denotes from which world the card comes from.