Seven Maidens

The Seven Maidens are a recurring group in the Legend of Zelda series. They are seven young women who inherited magical abilities from their ancestors, the Seven Wise Men. Six of the maidens are named after the color they represented and wear, with the exception of the seventh maiden, Princess Zelda. Although they possess many magic powers, they become captured by both the wizard Agahnim and the wind mage, Vaati. Although they have the same names, there are likely two different groups of maidens throughout Hyrule's history, possibly from the same bloodlines.

The Legend of Zelda: A Link to the Past
During Agahnim’s rise to power in Hyrule he began to capture and sacrifice each of the maidens one by one. By sacrificing the maidens he could reopen the Seven Wise Men seal on the Dark World and free Ganon from the realm. Agahnim was able to sacrifice all of the maidens except for Princess Zelda who was rescued by Link after she sent out a telepathic message to him, asking him to come to the castle and save her. Later on however, she was captured by Hyrulean Soldiers and sacrificed by Agahnim. After Agahnim had been defeated in the Light World, Link discovered that the seven maidens were still alive within the various dungeons in the Dark World. Link then began to free each of them from there respective dungeons and revealed their history, along with Ganon and Agahnim's plot. Eventually, once all of them had been rescued, they helped Link break through the barrier surrounding Ganon's Tower, where Link destroyed Agahnim and soon after Ganon himself. The Seven Maidens then returned to the Light World and celebrated the return of the real King of Hyrule.

The Legend of Zelda: Four Swords Adventures
In The Legend of Zelda: Four Swords Adventures the seven maidens were becoming worried about a dark energy they felt coming from the Four Sword Sanctuary, where Vaati was imprisoned at the time, and asked Link to protect them while they went and checked on the seal cast on Vaati. When they opened the portal to the sanctuary, they encountered Shadow Link, who then imprisoned them within seven crystals and placed them throughout various dungeons in Hyrule. Link then set off to rescue them. After Link had found them, he used the power to repel evil within the Four Sword he was wielding at the time, freeing them from their crystals. After each maiden was freed they used one of their magic spells, often the Fairy Spell, to transform themselves into fairies and guide Link to the next maiden. Along the way, they helped Link find the origin of Shadow Link and discover that a man named Ganondorf had stolen the Trident from the pyramid and used Shadow Link to free Vaati. After much traveling, battling, and searching, Link was able to save all of the maidens, who in turn, helped him defeat Ganon and seal him within the Four Sword. Once peace had been restored to Hyrule, they ventured back to each of their homelands within the land.

Trivia

 * In the original version of A Link to the Past, the Seven Maidens were said to be descendents of the Seven Wise Men. However this was the result of a translation error. In the Japanese version, the wise men were called the Seven Sages. This flaw was later fixed in the GBA/Four Swords version of A Link to the Past.