OOT-TP: The Great Migration

At the end of Ocarina of Time, Link and Zelda realise what a grand mistake they had made in opening the Sacred Realm as children, and Zelda sends Link back in time with explicit instructions not to make the same mistake again, beginning what me and Flat affectionately refer to as the Child-Timeline. More than a century later, the events of Twilight Princess take place in a new and different Hyrule, one so changed that we are barely able to recognise it. What happened in these years to transform this land so completely? Read on and find out!

What changed in Child-Timeline Ocarina of Time
When Link gets sent back, the important thing to remember is that he does NOT open the Sacred Realm. Ganondorf continues in his plan to acquire the spiritual stones, and as a result, Barinade kills Jabu-Jabu, explaining why he isn't present in Twilight Princess. Additionally, the Dodongo's Cavern remains unusable to the Gorons, leading them to search for rock sirloin in the depths of the mountain, via the Goron Mines. However, when Ganondorf discovers that even with the stones he is unable to open the Sacred Realm, he adopts the brute-force approach, leading an army of Gerudo and monsters on Castle Town. After sacking the town and destroying the castle without obtaining the Ocarina of Time (Which was most likely taken north with the escaping royalty and populous) , Ganondorf finally just destroys the Temple of Time, but finds he is unable to lift the Master Sword. Thus, Castle Town and the Temple of Time are left in the decrepit state we find them in in Twilight Princess. Eventually, Ganondorf's army is beaten back (Most likely by an army of Sheikah from the Hidden Village), and most of his Gerudo are killed in the process, explaining their lack of presence in Twilight Princess.

(Disclaimer: Ganondorf is not necessarily the one who attacks Castle Town and there is plenty of evidence against his doing so. However, an attack was obviously made, and Ganondorf is still the best theory we have so far. Other ideas are welcomed and appreciated.)

Sages in Child-Timeline
The sages in Child-Timeline are all spiritual beings similar to Rauru. Inhabiting the five temples, these spirits were killed off by the boss monsters Ganondorf sent to the temples in Adult-Timeline, with one unique and relevant exception: the Sage of Spirit. Even as a child in Ocarina of Time, Nabooru has already been called to the Spirit Temple, and Twinrova is already living there, leading us to believe that the original Sage of Spirit dies before or during Link's childhood in OOT, and therefore the Sage of Spirit in TP is most likely Nabooru.

The Lost Woods, Kokiri and the Great Deku Tree
The southern landscape of Hyrule is drastically changed during the years between Ocarina of Time and Twilight Princess, and a large portion of this stems from the expansion of the Lost Woods over much of what is eventually referred to as the Ordon and Faron provinces. The other noticeable change is that the Kokiri are no longer present, having either died out or, as I would prefer to believe, transformed into the monkeys seen in Twilight Princess (Thus, the Kokiri lack doubles in Majora's Mask because the monkeys are in fact their doubles). Gohma remains inside the Great Deku Tree long after his death and is able to locate and kill the Deku Tree Sprout, preventing a new tree from growing. Without his magic, the Kokiri are transformed back into forest creatures (Monkeys) and escape into the Lost Woods (Or die, if you really prefer). No longer kept in check by the Great Deku Tree, and with a nearly uninhabited expanse of land at their disposal, the Deku Scrubs (Or perhaps even the trees themselves) convert the majority of Hyrule Field and Castle Town into dense forest, eventually being referred to as the Faron Woods.

Ordon Village and Lon Lon Ranch
After completing the Cucco game at Lon Lon Ranch as a kid, Talon jokingly asks Link if he would like to marry his daughter, Malon. While it may have seemed like nothing at the time, we believe that Link does indeed marry Malon, and that their descendants, along with the descendants of Ingo and whoever else decided to stay behind, become the inhabitants of Ordon Village. While we have yet to agree on true lineages, a couple can be assumed with acceptable certainty. The pairing of Link and Malon most likely becomes the descendants of either Link or Ilia in TP (But hopefully not both!). Also, the goat ranch that Fado runs in TP may in fact be the very pasture that forms the center of Lon Lon Ranch in OOT, implying that he may be descended from Ingo, who takes care of the cows in OOT.

Well, that pretty much leaves us at the Divine Prank and, therefore, the end of the period known as The Great Migration. Stay tuned for more!