Setting Sun Star-vader, Darmstadtium

(This ability is active if you have four or more damage):[Choose a grade 3 or greater card from your hand, and discard it] When a Link Joker rides this unit, you may pay the cost. If you do, choose up to three of your opponent's rear-guards, lock them, choose your vanguard, and that unit gets +10000 until end of turn. (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.