Pay 3 Force Choose a Sith unit in each arena. Each of those units gets +2 power until end of turn unless your opponent puts a corruption counter on one of his or her units in each arena.
Keywords
Stealth
Stealth: An isolated, static ability that means, "This unit can't be attacked unless it's tapped or has damage counters on it." An untapped and undamaged unit with Stealth can still be affected by alternative types of damage. (Such as Overkill.) As long as the unit has any number of damage counters on it, it can't use Stealth.