When you deploy Jarael, you may remove up to 2 damage counters from one of your units in the Character arena.
Pay 2 Force Prevent up to 2 damage to one of your other units in the Character arena.
Keywords
Double Strike
Double Strike: An isolated, static ability played after the attack end POP that means, "You may choose a unit that this unit can attack. This unit attacks that unit. Play only if this unit just attacked and only if it tapped for that attack." The unit must tap for the first attack, not the second. If it untaps, it may double strike again. Double Strike doesn't allow you to attack your own units.