Mercadian Masques is the 18th expert level set, and the first set in the Masques block of cards. It is composed of 350 cards and new mechanics were Alternative Play Costs, Spellshapers, Rebels and Mercenaries.There were also spells that could be played for free when opponents had an opposing color. This was termed as emnity.
The notable cards in the set were Bribery, Squee Goblin Nabob, Cho-Manno, Lin-Sivvi Defiant Hero and Ivory Mask.I was apalled by the high number of useless commons and uncommons in the set. Most of the rares weren't up to par either. I think they did this to balance the play environment due to the overpowered Urza block. This set was garbage. I only liked playing with the rebels.