Shard

A shard, or arc, is a series of three colors in an unbroken chain on the color pie. The middle color in a shard is its primary color, allied to both of the shard's other colors.

Description
Prior to the official naming, Invasion block was the first multicolored set with some three-colored themes. Invasion and Planeshift were headlined by shard-colored Dragons as a reward for stretching the allied-color drafting. There were three cycles using the dragon's names, with four other cycles with [word]-Scape (Sun, Storm, Night, Thunder, and Thorn) as a name for the shards. These names did not stick, and three-colour spells were not developed further for many years.

The official term "shards" was established in the 2008 expansion Shards of Alara. It depicts the plane of Alara divided into five shards, each having only three of the five colors of mana. Each shard has its own flavor and gameplay mechanic related to its place in the color pie.

Bant
Bant features the Exalted keyword. Dominarian school of magic was Sunscape. Primary color is white.

Esper
Esper features a colored artifacts theme. Dominarian school of magic was Stormscape. Primary color is blue.

Grixis
Grixis features the Unearth keyword. Dominarian school of magic was Nightscape. Primary color is black.

Jund
Jund features the Devour keyword. Dominarian school of magic was Thunderscape. Primary color is red.

Naya
Naya features a 5-power matters theme. Dominarian school of magic was Thornscape. Primary color is green.