Star-vader, Garnet Star Dragon

:[Legion 20000]"Companion Star Star-vader, Photon"(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) :When this unit [Legion], choose a rear-guard in your opponent's front row and back row, and lock them. (The locked card is turned face down, and cannot do anything. It turns face up at end of the owner's turn.) :When this unit attacks a vanguard, this unit gets +2000 until end of that battle.