Add 2 counters to your Resource. Play only during your build step.
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."
Reduced Cost
Reduced Cost X: A selective, static effect that means, "This card’s cost is X if the listed condition is met." Reduced Cost on cards refers to the build cost, except for Battle cards, where it refers to the Force activation cost. For this keyword, the conditional statement will always start with "If" for clarity. The condition must be met in order for you to be able to pay the "Reduced Cost."