The maximum number of colors of mana you can spend to cast a spell is five. Colorless is not a color. Note that the cost of a spell with converge may limit how many colors of mana you can spend.
Roilmage's Trick
If there are any alternative or additional costs to cast a spell with a converge ability, the mana spent to pay those costs will count. For example, if an effect makes sorcery spells cost {1} more to cast, you could pay {W}{U}{B}{R} to cast Radiant Flames and deal 4 damage to each creature.
You can cast Roilmage’s Trick even if your opponents control no creatures. You’ll simply draw a card.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Johann Bodin
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
