As a Hero, Mystique acts as a skilled assassin. She uses her spymaster abilities to keep the Villain from adding Civilians and Thugs to a Location near her, potentially preventing dangerous Overflow effects. And of course, she can change her appearance, fooling the enemy and redirecting any damage directed at her towards Thugs or Henchmen in her Location.
As a Villain, Mystique has a very specific mission: assassinate Senator Kelly to stop the Mutant Registration Act. The Senator Kelly token starts with the Heroes, and they can take him with them whenever they move. Senator Kelly is vulnerable to any effects that target Heroes, however, Heroes in his Location can always choose to take damage directed at him. And they will need to do so time and again, since if Senator Kelly takes any damage, he is killed and Mystique wins. To make things harder, whenever there’s an Overflow or a Hero is KO’d, Senator Kelly moves (or is it Mystique in disguise?).
Using her metamorph abilities, Mystique fools the Heroes and redirects any damage to her towards her Henchmen. And speaking of Henchmen, the Brotherhood of Mutants is always at her side. Avalanche crumbles all Locations around him, attacking Civilians or Heroes there. Destiny helps move Senator Kelly away from the Heroes’ protection. Pyro incinerates Heroes all around him. And Toad leaps from Location to Location, attacking Heroes.