As long as you have a unit in each arena, Slave I gets +2 power.
Avenge 2
Pay 2 Force Persuade 2
Keywords
Avenge
Avenge X: A cumulative, triggered ability that means, "Whenever damage from an attacking unit causes one of your other units in the same arena as this unit to be discarded, this unit does X dice of damage to the attacking unit when the attack ends."
Bounty
Bounty: [bonus]: A layered ability triggered during a unit discard that means, "When another unit is discarded by damage from this unit, you gain the following when your next build step starts." Bounty triggers even if the attacking unit leaves play. Bounty works in the build zone. You will gain the bounty even if the attacking unit is sent to the discard pile. The unit can't collect a bounty on itself.
Persuade
Persuade X: An activated ability that means, "Prevent up to X damage to this unit, and the attacking unit, if any, loses power for its next attack equal to the amount of damage prevented this way."