Pay 2 Force, pay 1 build, and Put a corruption counter on a unit in any arena. Play only during your build step.
If Palpatine is discarded from play, remove all corruption counters from your opponent's units.
When all of your opponent's units have corruption counters on them, you win the game.
Pay 1 Force Evade 2
If R2-D2's Heroism is played, you can't win the game.
You can't remove corruption counters from Pilots on units.
Palpatine's third effect is Only concerned with units in play.