Blue Storm Dragon, Maelstrom

: 1 When an Aqua Force rides this unit, you may pay the cost. If you do, choose up to one of your vanguards, until end of turn, it gets +10000, and "Wave-4th time or more (This ability is active during the specified battles of each turn):When this unit attacks a vanguard, draw a card, choose one of your opponent's rear-guards, retire it, and until end of that battle, your opponent cannot call grade 0 cards from hand to .". Wave-3rd time or more (This ability is active during the specified battles of each turn):When this unit's attack hits a vanguard, search your deck for up to one card with "Maelstrom" in its card name, reveal it to your opponent, put it into your hand, and shuffle your deck.