Link's Uncle

Link's Uncle is a character featured in A Link to the Past.

Biography
A former knight in service to the royal family of Hyrule, Link's Uncle has been Link's guardian for some time. He teaches him how to effectively use a sword in the game.

Link, woken in the night by a telepathic plea from Princess Zelda, finds his uncle about to leave the house with a sword and shield in hand. Seeing Link wake, he tells him not to leave the house, promising to return for morning. Ignoring his instructions, Link sneaks into the palace via the sewers in an attempt to rescue the Princess himself. Here, Link finds his uncle mortally wounded, unable to go on. Entrusting him with the task of saving the Princess, he gives Link his sword and shield and teaches him the Spin Attack before dying.

At the end of the game, after Ganon has been defeated and Link makes a wish on the Triforce, Link's Uncle is shown to be alive and well in the credits, where he seems to be practicing sword fighting with Link in front of their house.

In the Game Boy Advance version of the game, Link's Uncle supposedly appears in the Palace of the Four Sword, wounded. However, when Link speaks with him, he transforms into Blind the Thief.

A Link to the Past comic
In the A Link to the Past comic, it is mentioned that Link's Uncle adopted Link  because his parents  stumbled into the Dark World, shielding him from the intrigues of the  Royal Family.

At the beginning of the comic, Link's Uncle goes to Hyrule Castle to confront Agahnim while Link is still asleep. When Link wakes up in his house to find that his uncle is missing, he panics but heads to Hyrule Castle after hearing Princess Zelda's plead. Link sneaks into the castle and sees his uncle dueling Agahnim, who deals a deadly strike to Link's uncle, saying that anyone who    challenges him will meet their doom, and promptly vanishes afterward. Link rushes to his uncle's side and receives his sword and shield from him. Before passing out, Link's Uncle explains that after the young hero rescues Zelda and the people in the Dark World, he might be able to meet his parents. After he passes away, Link promises to defeat Agahnim with the use of the Master Sword to avenge his uncle's death.

Once Link reaches Death Mountain, he stumbles upon a portal to the Dark World, which activates itself and shows a vision of his parents standing with his uncle. Link's Uncle is not seen again until the end of the comic after Link defeats Ganon and peace returns to Hyrule: at Hyrule Castle, Link sees a vision of  his father, mother and uncle,  who  congratulate him on his difficult  victory and tell him to never  forget  the efforts of the many  generations of knights and Wise Men  that preceded him.

Trivia

 * Early in the game, Link's uncle says "Zelda is your..." before falling unconscious. This caused some people to speculate that the full sentence would have read "Zelda is your sister", possibly in relation to the film Star Wars Episode VI: Return of the Jedi (less popular sentence endings included "ally" and "only hope"). The Japanese version of the game contains a slightly different line ("お、お前は、姫の…　…. ", literally, 'y- you are the Princess's...'). In the Game Boy Advance version, this line is instead attributed to the impersonator of Link's Uncle in the Palace of the Four Sword.
 * Link's Uncle shares some of his physical traits to Tarin from Link's Awakening, especially how Link's Uncle is depicted on official artworks.
 * Link's Uncle also shares similarities with Rusl from Twilight Princess. They are both swordsmen who serve as Link's mentors, both were wounded during the game, they have the same in-game hairstyle, and they both have facial hair which is a different color than their hair.
 * The official Japanese soundtrack CD of A Link to the Past contained a short radio drama. In it, a young Link was placed under the care of Zelda's nurse, Egorowa, and her husband Alphon - who he calls uncle. It is unclear if this meant to be a preview of a pre-Ocarina of Time version of the Imprisoning War or simply an alternate history.
 * Link's Uncle is briefly seen in the Japanese commercial for A Link to the Past.