[AUTO](VC):[Choose one of your rear-guards with "Rex" in its card name, and retire it] When this unit attacks a vanguard, you may pay the cost. If you do, draw a card, and this unit gets [Power] +3000 until end of that battle.
[AUTO]:[Choose a card from your hand, and bind it face up] When this unit is placed on (VC) or (RC), you may pay the cost. If you do, choose one of your other rear-guards with "Rex" in its card name, that unit and this unit get [Power] +2000 until end of turn.