Note: Link is very young. Perhaps 4-7? This is before OoT.
"Great Deku Tree, look!" A small voice called up joyfully, and soon the owner of the voice, a little boy clad in green, came into sight as he scrambled up the large roots of the giant tree. "Look what I found!" He thrust his hand out, cradling in his hand a rock as if he held a treasure. Such are the ways of the very young. The tree chuckled dryly, saying "My, Link, now what is it you have brought me?" Link beamed proudly. "It's a rock! And it's blue!" He gazed at his insignificant treasure, that in his eyes was worth all the world. Looking down at the boy, the Great Deku Tree thought the same thing about him. Small, and maybe insignificant, but dearer to the heart than the whole world. He sighed as he remembered the night Link came to the Kokiri. It was dark and the wind raced sharp and icy across the land. He had thought it was thunder when he heard the hoof beats. But it was a woman, and she brought Link with her, and left him at the foot of the tree. Bowing, she prayed-Great Deku Tree, please…! Please save my son! And then she was gone, and the babe howled with the wind, screaming its loss and pain to the world. The Deku Tree thought of that night, and knew that someday Link would not be his insignificantly loved Kokiri child. He would leave the forest, he would grow old and grey, he would forget his home. Because Link was not a Kokiri; he came from the Outside, and wandering was part of his very soul. Link stopped chattering, sensing the growing fear of his old friend. He stood, and with all the earnest innocence of a small child, he laid his hand upon the bark of the ancient tree. Looking up he whispered "Deku Tree, why are you so sad?" The Great Deku rustled guiltily, for a moment surprised that his young charge was so perceptive of his moods. "Ah, young friend. Do not trouble yourself with my old uncertainties." He would tell him when he was older. But now. Dear Farore, not now. The little boy tilted his head, as if sensing a great story, than he brightened. "Will you-" The Tree chuckled. "Tell you a story? Of course. Settle down now." And the tale began.
Do you know the constellation Starwind? Yes? But you do not know the story behind it, do you? No? Let's see, it all started long, long ago, when the world we knew consisted only of Hyrule. The maps stopped at the Great Sea, which stretched on forever, never stopping. Nobody even thought of sailing; to them, it was inconceivable. Such a thing did not exist. Until one day, when a poor, restless farm boy decided to try his luck. You see, he'd been watching the sea, and had taken note that wood seemed to float on it. He thought, why not? For as I have said, he was an adventurous soul. He set to crafting a boat, but it took many, many years to complete, for you must remember, there had never been such a thing before. When he finished, he was not so young anymore. However, he would not give up; he set off the morning after he completed Starwind, never once looking back. Many thought him mad, and shook their heads as they watched him leave. He sailed for many years, roaming the world. He found many new lands, but none of them were home. Neither was the land he'd left though, and so on he wandered, never turning back, always searching, searching. Many adventures he had, but still he was not satisfied with the world. He had no-one to tie him to it. He had no wife, no children. He had never grown close to his siblings, because he was always gone. His parents had passed away long ago. He had none to tie him to Earth, and so he left it. Do not ask me how, for there are many theories. Some say he finally sailed over the edge of the world. Some say he died, of old age or otherwise. Some say he passed a holy boundary. Some say he crossed a bridge. Some say he made a bargain with the goddesses themselves, and was lifted above our world, sent to sail the heavens. But whatever the reason, one day he disappeared from our world, only to be seen in the stars.
Link gazed up at The Great Deku Tree as he finished his story. He had an awed smile upon his face, and time was forgotten as he contemplated the many places one could travel to. "Do…Do you think I will travel someday?" The deku Tree smiled down sadly at Link. "I am sure of it, Link." The small child grinned blissfully, but soon faded, as once again he felt the shift of his friend's mood. "Is that why you were sad earlier?" The tree sighed. "Do not be troubled, Link. I am simply too old, and I am afraid that you will leave us soon." Link laughed a cheerful little burble, patting the Deku Tree gently. "Do not be sad! I will not leave forever!" The Deku Tree chuckled with him, but he did not believe that Link would ever come back when he left. He was not, after all, Kokiri. He did not need the forest. But the forest needed him. The Deku tree rustled softly. "It has become dark, Link. Shouldn't you be back at the Kokiri village? Saria will be looking for you. You shouldn't worry her so." Link gasped. "I should have been back by nightfall…" He looked back up at the Tree. "Do you think she'll be mad?" He whimpered quietly. The Tree chuckled. "No, little friend, but you must not worry her anymore. Make haste, Link!" He chuckled as he watched Link scurry back to the village, shouting his goodbyes over his shoulder. He sighed again, and closed his eyes. Goodbye, small one. Your time with us is borrowed, and we will miss you when you leave us. Goodbye. The sun slipped completely below the trees. Goodbye.