The Windy card is the one that started it all. When she said its name, all of the other cards blew away! It is one of the four element cards. These cards can cause great distruction when they all come together. Even though it doesn't seem like Windy is the strongest card, it has known Sakura the longest, so it is really her strongest ally among the Clow Cards. She used it in the last judgement to create a cage in order to defeat Yue without hurting Yukito.