Nebula Dragon, Cosmic Dawn Dragon

-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] this card on your from face down. :When this unit attacks, 1, look at the top seven cards of your deck, choose up to two cards from among them, put them on as locked cards, and shuffle your deck. Then, choose any number of your locked cards, and unlock each card or return it to your hand. For each card returned to your hand, your opponent chooses one of their rear-guards, and locks it.