Magic: the Gathering's mana system is divided into five colors that constitute the color pie. Wizards of the Coast developed the color pie early on to give the game some cohesion and make decks feel distinct based on which color/s of the pie those decks use. From August 1993 to now, the color pie has served its purpose well, but WotC and MtG players alike still see some room for improvement.
Source：https://www.cbr.com/mtg-color-pie-gaps-need-to-be-fixed/
