Dragon Knight, Imahd

(This ability is active if you have one or more face up G units in total on your or G zone): 1 When your opponent's rear-guard in the same column as this unit is put into the drop zone due to an effect from one of your cards, you may pay the cost. If you do, until end of turn, this unit gets +2000, and ":At the beginning of the damage step of the battle that this unit attacked, if the number of your opponent's guardians is one, choose one of your opponent's guardians, retire it, and that unit's effects with "cannot be hit" are nullified.".