Multicolor Matters decks reward spells or permanents that have more than one color. They frequently use gold cards throughout the mana curve and therefore require particularly careful mana fixing.
Pillar of the Paruns provides mana specifically for multicolored spells, while Glass of the Guildpact strengthens multicolored creatures. Niv-Mizzet Reborn goes considerably further by rewarding decks built across all ten two-color combinations.
