User blog comment:Guidorz/Jokers Ruling/@comment-25236516-20180116231908/@comment-25236516-20180116235914

You're right about the colorless part. However, you don't need to pay 2 fire mana to play a fire jokers, just one, which applies to all other kinds of creatures too. As long as 1 card that pays that color (even if it pays 0 mana) is tapped, then you can summon a creature of that color. Colorless cards don't pay for colors but they still pay for the mana cost.