Star-vader, Imaginary Plane Dragon

:"Flash Gun Star-vader, Osmium"(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) : 2 If this unit is [Legion], for each unit in your middle column with "Star-vader" in its card name, choose up to one of your opponent's rear-guards, and lock it. (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.