Ciela

Ciela (シエラ, Shiera) is the first Fairy Companion that helps Link in Phantom Hourglass.

True Identity
She first meets Link when he lands on Mercay Island and takes him to her "grandpa", Oshus. Eventually she and Link begin to travel together along with Linebeck, whom she doesn't like much and often fights with.

After beating the Temple of Courage in Molida Island, however, instead of a colorful fairy, another white fairy much like Ciela appears. Link goes to Oshus, who also has traveled to Molida during that time, and uses his staff to fuse the new fairy and Ciela together, revealing that she is in fact the Spirit of Courage, and whose true color turns to be yellow.

Prior to the game's beginning, Ciela had split herself in two to prevent Bellum from sealing her away like he had with the other spirits.

Abilities
By collecting 10 Courage Gems and offering them at Spirit Island, Ciela can allow Link the ability to perform a Sword Beam. Collecting 20 gems doubles the width of the beam.

In the final boss fights, Ciela provides Link with Phantom Spheres, allowing him to temporarily freeze time. It is around this time that Ciela fully regains her memory as Spirit of Courage and Time. The final scene before the credits is Ciela saying her goodbyes to Link and Linebeck. She eventually gains respect for Linebeck as he does for her, and is sad to see him go.

Trivia

 * During the final battle with Bellum, Link cannot use the Sword Beam due to Ciela's capture at the hands of Bellum.
 * Ciela is similar to cielo, the Spanish word for "sky" (although the name can also connotate "heaven"), which is appropriate given the nature of Ciela's character to fly around the screen. Her name is also appropriate considering courage is frequently associated with the element of wind, such as Farore's Wind as well as Link's role in The Wind Waker.
 * Ciela is depicted with three colorations: white at the beginning of the game, yellow after her true identity is revealed, and blue on official artworks. Ciela's yellow color is unique because the color signifying courage is typically green in the Legend of Zelda series.
 * Because the voice acting used for Ciela in the game is taken from Navi from Ocarina of Time, and early trailers for the game featured the fairy speaking yet did not show Ciela's name, many fans initially believed she was Navi.
 * Ciela bears resemblance to Tatl of Majora's Mask, due to the yellow color she takes when revealed to be the Spirit of Courage. The Spirit of Healing from Spirit Tracks bears resemblance to Ciela's first form, due to her white color.