This is the timeline where Ganondorf killed Link in his final battle with him, leading to the Imprisoning War described in A Link to the Past's backstory.
Before The Adventure of Link
Long ago the King of Hyrule used the full triforce to ensure a golden age upon Hyrule, however when age started to catch up with the King, the monarch realized his son was an unworthy heir as the the mysterious court Magician had corrupted the boy's ambition and now he selfishly aspired to rule Hyrule at any cost.
Fearing the repercussions of his son or the magician getting their hands on the full Triforce, the King entrusted the Triforce of Courage to a humble sage who would hide the Triforce of Courage in the Great Palace and create monster guardians to ensure only a hero that was truly worthy could obtain the Triforce. Only the King's daughter was told the location of the Triforce of Courage.
The Adventure of Link
When Link destroyed the Thunderbird and reached the end of the Great Palace, he encountered the sage with the Triforce of Courage. The sage was unsure Link was worthy and as a final test waved his staff to bring Link's Shadow to life, filled with all of Link's inner evil.
Link's Shadow was defeated and destroyed by Link, symbolizing the hero overcoming his inner demons. With Link's victory, the sage knew he was the hero he had waited all these years for and entrusted the Triforce of Courage to him.
Manga and Comics
In the manga adaptation of Adventure on Link by Yuu Mishouzaki, Dark Link is instead the alternate form of Ganon, the result of his followers sprinkling Link's blood on his ashes.
In the Valiant comics adaptation, Link's shadow is known simply as Shadow. He is a shapeshifting monster created by Ganon. In addition to being able to take the form of Link, Shadow also takes Zelda's form.
In the Maru Ran manga, Link's Shadow is created from Link's reflection in the mirror by the guardian of the TriForce. When the bloodthirsty clone comes into existence, he kills Link's sentient Parrot friend, WAtto in cold blood and tries to murder Link. When Link's Shadow is destroyed by Link, the guardian revives Watto and grants Link the Triforce of Courage.
- Link's Shadow, Dark Link, and Shadow Link were once considered the same entity. However, since the release of the Hyrule Historia, it has been confirmed Link's Shadow is a separate entity from the two others. Though Zelda Universe treats the three as one.
- Although Hyrule Historia calls him Link's Shadow, he is referred as Shadow Link in NES Remix 2 and Dark Link on Zelda.com. His true name can be debatable.
- There is an easy way for Link to defeat Dark Link. If Link stands in the corner and kneels, he can easily stab Dark Link. After this happens, Dark Link will fall back before approaching Link. This process can be repeated until Dark Link is defeated.