Perdition Dragon, Break Down Dragon

:[Legion 20000]"Perdition Dragon Knight, Tarayev"(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) : 3 If this unit is [Legion], choose one of your opponent's rear-guards, and retire all of your opponent's rear-guards in the same column as that unit. Then, if the number of rear-guards your opponent has is two or less, choose a card from your damage zone, and turn it face up. :When this unit attacks a vanguard, if you have another unit in your middle column, this unit gets +3000 until end of that battle.