Perdition Dragon, Pain Laser Dragon

:[Legion 20000]"Perdition Dragon, Menace Laser Dragon"(If your opponent's vanguard is grade 3 or greater, this unit may return four cards from your drop zone into your deck once, search your deck for the specified card, and Legion) : 1 When this unit [Legion], you may pay the cost. If you do, choose one of your opponent's rear-guards, and retire all of your opponent's rear-guards in the same column as that unit. : 1 When this unit attacks a vanguard, you may pay the cost. If you do, this unit gets +3000 until end of that battle.