The Zelda Ocarina Legend of Time is one of the most famous titles in the saga and most revolutionary on the Nintendo 64 console, which can be considered the Zelda with the darkest and saddest ending. I know that many who played the title in their time were children, so they did not understand the story very well and we even ignored it for being an incredible adventure game.
Who is the Hero of Time?
Link is a Hylian who grew up under the warm cloak of the Kokiris, a race of children who never grow or mature, these under the care of their guardian and father the Great Dawn Deku.
Why is the title with the saddest ending considered?
Well, for that we must start from the beginning of the story and that link was considered a Kokiri without a fairy, this had its reasons since he was a Hylian himself, but soon this ends when the Great Deku Tree is affected by a hex sent by Ganondorf, the evil Gerudo who wanted to seize the medallion that the Great Deku Tree kept with him, so the Great Deku Tree was forced to ask for help from Navi, a fairy without Kokiri, to little Link. The Great Deku Tree knew with wisdom what fate awaited this little Hyliano boy. Medallions: After Link defeats the hex inside the Great Deku Tree, the first blow of our little hero passes, and it is that despite having completed his mission well, he loses his father and protector. Which orders him to leave the forest and meet Princess Zelda, someone who would guide him to his destination. Once he met the Princess, our little hero knows the location of the two missing medallions, where the first one was delivered by his father and protector; the second was delivered by Darunia who considered him her family for having saved her people from starvation; the third of Ruto the princess of the Zora for having saved her from inside the Guardian Yabu Yabu.
We see that our little hero in his adventure built ties, but that later they ceased to exist.
Master Sword and The 5 Guardians:
After having successfully obtained all three medallions and witnessed the event of Zelda's escape from the hands of the Evil Gerudo, Link goes to the temple of time and draws the sword, giving way to Ganondorf to the Holy Shrine where the Triforce is located. Despite what happened, the time sage is frozen Link for 7 years until his adulthood, because he was too young to handle Master Sword. After 7 years Link wakes up from his long torpor and the current situation is explained to him, at that moment Link learns that he is not a Kokiri but a Hylian.
Final:
After releasing the guardians and defeating the Evil King Ganon, Zelda decides to send Link to his respective timeline, where Link would be responsible for reporting what happened to the King before Ganondorf acted, this unexpected ending led to our young Hero was never remembered as the great savior and that the bonds he had built in his adventure were null.
That is not all, Link was abandoned by his faithful companion Navi, and it is also that he will never be able to return to where his home was always, Kokiri Forest, where it is impossible to enter without a fairy because otherwise, you will become Stalfos or Skull kid.
Summary:
In conclusion, his exploits will never be remembered and his friendships never existed, abandoned by his faithful friend, and unable to return to his former home. It is for all this that The Legend of Zelda Ocarina of Time is the game with the darkest and saddest ending.