Vorthos, Steward of Myth is a mythic Legendary Creature — Human Gamer card from Unfinity (UNF), collector number 251. Current market price: $0.27 (foil $0.34), TCGplayer market prices via Scryfall.
As Vorthos, Steward of Myth enters, choose a named Magic character. Each spell you cast with the chosen character in its name, flavor text, or art costs {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.