Stealth Dragon, Tenrei

:During your turn, your vanguard with "Shiranui" in its card name gets all of your opponent's vanguards' card names, clans, races, and nations. :[Put this unit into your soul] When an attack hits a vanguard during the battle that this unit attacked or boosted ([Boost]), you may pay the cost. If you do, your opponent chooses a card from his or her hand, and discards it.