Color indicator

The color indicator is a characteristic of an object. It is printed to the left of the type line directly below the illustration. It consists of a circular symbol filled in with typically one but sometimes more colors. A color indicator is usually found on cards without a mana cost that however have to convey color information.

History
The color indicator was introduced with Innistrad to define the colors of the back faces of double-faced cards without resorting to characteristic-defining abilities. With the following Oracle update, some cards (such as Crimson Kobolds and Evermind) received errata, removing a characteristic-defining ability defining the card's color, and receiving a color indicator instead. This produced some functional changes, such as Crimson Kobolds being affected by Muraganda Petroglyphs, and players being unable to splice Evermind onto Arcane spells in order to change the original spell's color.

Multicolored color indicators
Only a few multicolored color indicators exist.

Arlinn, Embraced by the Moon and Garruk, the Veil-Cursed   are two-colored examples.

Grimlock, Ferocious King (, silver-bordered) and Nicol Bolas, the Arisen</c> are three-colored examples. For a while, Transguild Courier</c> featured a five-colored indicator  in Gatherer but was never printed with it. When a five-colored indicator was considered for Sphinx of the Guildpact</c>, no version was deemed suitable. This resulted in the use of rules text, and a similar oracle update for Transguild Courier</c>.