Hero's Shade

The Hero's Shade is a character from The Legend of Zelda: Twilight Princess. Once a famed swordsman of Hyrule, he died with the eternal regret of never having passed on his knowledge of the art of the sword. The Hero's Shade manifests itself as a red-eyed, golden wolf in the world of the living.

Being a skeletal spirit, he is immortal and cannot be damaged during training sessions with Link. The Hero's Shade's appearance, in his ghost form, is very similar to that of the Stalfos, suggesting that he might be one.

Biography
When Link, a young boy from Ordon Village, is pointed out as the one destined to overcome the evils of the King of Twilight, the Hero's Shade sees the potential to be a master swordsman within him, and approaches him on his way to the Forest Temple. Link is taken into another world, the realm of the Hero's Shade.

The Hero's Shade offers Link his knowledge of the sword. After teaching him the first skill, the Ending Blow, he tells Link that in order to meet him again, he must, in wolf form, approach a Howling Stone and howl the notes that the stone echoes. When Link successfully performs this, the golden wolf manifestation of the Hero's Shade will appear somewhere in the land of Hyrule. Link, in his normal form can then approach the wolf to once again enter the other world and learn a new skill. However, before he can learn a new one, he has to prove his mastery of the previously learned skill by utilizing it against the Hero's Shade.

When Link has learned six of the skills, he makes his final appearance in front of Hyrule Castle and teaches him the Great Spin Attack. His destiny fulfilled, the Hero's Shade then passes on to the world of spirits.

Possible Origins
The Hero's Shade's final words to Link are "Go forth and do not falter, my child," which has led many to believe he is the spirit of the Hero of Time, Link's ancestor famous for his deeds against Ganondorf during the Imprisoning War and for saving the land of Termina from destruction at the hands of Majora. This theory is compounded by the fact that the Hero's Shade says that he once took up the role as hero. It should also be noted that the songs to summon the Golden Wolf are songs from Ocarina of Time and Majora's mask. In the Gamecube version of Twilight Princess, the Hero's Shade is left-handed. Link from Ocarina of Time and Majora's Mask is also left-handed. If looked at carefully the Hero's Shade's sword closely resembles the master sword. The only difference is the hilt.

A small side note that further supports this theory is that his name is Hero's Shade. Hero referring to Hero of Time, and a Shade is a kind of spirit, one who has left an imprint of themselves behind when they die.