Sheik

A mysterious warrior with great wisdom and strength, Sheik is the last surviving Sheikah in Ocarina of Time. He aids Link on his quest without really describing who he is or why he is aiding Link. He has great advice and knowledge of the world, making him an invaluable ally for Link. Sheik is also the teacher of the various teleportation songs that Link uses later on in his quest.

Attributes of Sheik
Sheik Quotes from Ocarina of Time

Soundtracks/Themes
Every appearance Sheik has made in Ocarina of Time is accompanied by a melodic tune played by the harp. Titled Sheik's Theme the theme is composed by Koji Kondo and is featured in the official game soundtrack.

Ocarina of Time
Sheik reveals himself to Link shortly after Link is freed from the Chamber of Sages after his seven year imprisonment. He informs that Link must awaken the seven sages in order to bring peace back to Hyrule. Alerting him of the need to possess a new tool in order to enter the temples he then disappears, later reappearing when Link arrives at the Sacred Forest Meadow. He tells Link about the warp songs used to teleport to temple entrances and teaches him the Minuet of Forest before disappearing again. Further along Sheik approaches Link at the Fire Temple entrance in the Death Mountain Crater, teaching him the Bolero of Fire before walking away, using a wall of flame to halt Link's inquiring advance.

Sheik once again mysteriously appears in the Ice Cavern to inform Link of the fate of the Zoras and to teach him the Serenade of Water. He then awaits outside the Water Temple for Link to free the temple and awaken the Water Temple sage before disappearing once again. When Kakariko Village comes under attack from a mysterious force Link discovers that Sheik is already there and together they encounter, and are defeated by, an invisible monster thought to be the Shadow Spirit. Sheik teaches Link the Nocturne of Shadow and urges Link to help Impa fight the Shadow Spirit. When Link discovers that he must venture back in time in order to do so Sheik offers a helping hand, informing him on how to use the Master Sword and the Pedestal of Time in order to travel back and forth through time. He teaches Link the Prelude of Light then once again vanishes.

At the entrance of the Spirit Temple Sheik appears, having being waiting for Link from atop a large rock formation, and once again informs Link that he must enter the temple as a child, utilizing the Pedestal of Time in the Temple of Time. He gives Link a lesson on performing the Requiem of Spirit before using the desert winds as cover to vanish.

With all six sages freed Link is instructed to return to the Temple of Time where none other than Sheik awaits. Sheik congratulates Link on his efforts and offers an explanation on what exactly happened to Hyrule during Link's disappearance before finally revealing her true identity, as Princess Zelda.

Poems
Before Sheik teaches Link warp songs, she tells him a Poem pertaining to the person he must rescue, or leaves a hint about how to restore a sage.

A few poems by the word include:

When you first reach the forest temple as an Adult, Sheik appears before Link. Before she teaches him: The minute of Forest, she tells him:

"The flow of time is always cruel... Its speed seems different for each person, but no one can change it... A thing that doesn't change with time is a memory of younger days... In order to come back here again, play the Minuet of Forest."

- Sheik

When you reach the Temple of Time, after completing the Forest Temple Sheik tells Link:

"In order to awaken all the other Sages, you must become even more powerful. You must travel over mountains... under water... and even through time..."

- Sheik

and teaches him the Prelude of Light.

After you receive the iron boots in the Ice cavern as Adult Link, Sheik gives Link the Serenade of Water and tells him:

"Time passes, people move.... Like a river's flow, it never ends... A childish mind will turn to noble ambition... Young love will become deep affection... The clear water's surface reflects growth... Now listen to the Serenade of Water to reflect upon yourself...."

- Sheik

When in front of the Spirit temple as adult Link, Sheik teaches Requiem of Spirit, and says,

"Past, present, future... The Master Sword is a ship with which you can sail upstream and downstream through time's river... The port for that ship is in the Temple of Time... To restore the Desert Colossus and enter the Spirit Temple, you must travel back through time's flow... Listen to this Requiem of Spirit... This melody will lead a child back to the desert."

- Sheik

After crossing the broken bridge of Death Mountain, Sheik appears and tells Link:

"It is something that grows over time... a true friendship. A feeling in the heart that becomes stronger over time... The passion of friendship will soon blossom into a righteous power and through it, you will know which way to go... This song is dedicated to the power of the heart... Listen to the Bolero of Fire..."

- Sheik

After the Water Temple, going into the graveyard of Kakariko Village, Sheik appears before Link and tells him:

"There is an entrance to the Shadow Temple beneath the graveyard behind this village. The only thing I can do for you is teach you the melody that will lead you to the Shadow Temple... This is the melody that will draw you into the infinite darkness that absorbs even time... Listen to this, the Nocturne of Shadow!!"

- Sheik

Twilight Princess

 * According to the Super Smash Bros. Brawl official site, a design of Sheik was drafted as she might appear in Twilight Princess, but this idea was later scrapped. Her Twilight Princess model was used in Super Smash Bros. Brawl.

Super Smash Bros. Melee
In Super Smash Bros. Melee, Zelda has the option of transforming into Sheik. To do this, you must press down the analog stick while pressing the B button. Sheik has a completely different moveset than Zelda. Sheik's moves and weapons are quick and similar to those of a ninja. Sheik is an extremely speedy character and for this reason she could be a bit difficult to control. Although she has an original moveset, she is found to have similarities with Captain Falcon. In Melee the two of them have a more powerful star rod attack. In the game, Sheik is always referred to as a female.

Super Smash Bros. Brawl
Sheik appears again in Super Smash Bros. Brawl. Although she did not appear in Twilight Princess, the character model was based on a design drafted during the game's development. She has mostly the same moveset from Melee, and shares a Final Smash with Zelda, the Light Arrows.

Ocarina of Time manga
Sheik first appears to Link having tended his wounds after being defeated by Volvagia. Sheik is a spy for Ganondorf, and later shows up to tell Link a rumor that Princess Zelda had been spotted in the Desert of Illusions, before vanishing again. On Link's way through the Desert, he nearly succumbs to blistering sands before Sheik pulls him out, and continues to travel with him. Later that night, Link is be attacked by illusions and images of his past, but Sheik is unaffected; Link wonders if it could be due to a lack of past in Sheik's life. Once reaching the Gerudo Fortress, Sheik knocks Link out, and the Hero is captured.

Once Link frees himself, he fights through the ranks of Gerudo, before Sheik comes to him with his sword and shield. Throwing them to Link, Sheik turns on the invisible Twinrova, who were watching nearby. They are enraged as Sheik explains to have always been on Link's side, and attacks.

After escaping with the unconscious Sheik, Link finds a cave to rest in. He leaves to find water, flustered after getting too close to Sheik. He returns to find that Sheik, having awoken with the face wrappings off, appears to be female. Fully transforming, Sheik is revealed to be Zelda, who later explains that she had Impa lock her consciousness away, and assume the guise of a Sheikah boy.

Gender Issues
As Sheik spends most of the latter part of the game disguised as a male, many fans have argued to Sheik's true identity. There is no hint given in the game that Sheik is in fact a male; however, at one point Ruto refers to Sheik as a "he". This is most likely explained by Ruto being unaware of Sheik's true nature. Sheik's build is more suggestive of a male.

Various theories to Sheik's true gender exists, but few official statements have been released clarifying if Sheik is male or female. In the Ocarina of Time manga, which deviates from canon, Princess Zelda had, instead, sealed away her consciousness and transformed herself into the Sheikah male, Sheik. However, in Super Smash Bros. Melee, Sheik is referred to as a "she", as well as the character summary of Sheik on the official website to the Zelda series. However, Melee is not part of the official Zelda canon.

The greatest supporting statement of Sheik's sex is in the trophy information. After beating the Classical mode in Super Smash Bros Melee, using Sheik or Zelda, Sheik's trophy information reveals that although Sheik is a cleverly disguised character, her physical appearance stays the same, but her clothing changes. Most likely Nintendo wanted people to know that Zelda is the same sex as Sheik, female.

Also, a little known fact from the dictionary; A Sheik in middle Eastern culture is defined as "a women wearing enough clothing to prevent her skin from being shown." Hinting that Sheik is a disguised woman.

There are some rumors about Eiji Aonuma explaining about Sheik's gender, telling he is actually a male. However, these rumors have not been proven true as there is no written interview or anything to prove it.

Trivia

 * In the game Paper Mario, released two years after Ocarina of Time, there is a Little Mouser king named Moustafa. To keep himself from being found, he disguised himself as a information dealer named Sheek, most likely a reference to Sheik.