Brawler, Fighting Dracokid

:Forerunner :[Put this unit into your soul] Choose one of your vanguards, and it gets ": 1 During your turn, when your opponent's rear-guard in the front row is put into the drop zone, and your vanguard is Legion, you may pay the cost. If you do, choose one of your opponent's rear-guards in the same column as the that the rear-guard was on, and retire it." until end of turn.