Dragon Undead, Ghoul Dragon

(Bind zone):[ 1 & Retire one of your rear-guards], choose up to six other normal units from your bind zone, return them to your deck and shuffle it. If you returned four or more, call this card to . :When this unit attacks a vanguard, [ 1 & retire one of your other rear-guards], choose one of your opponent's rear-guards, and retire it.