Slumber of Restoration

The Slumber of Restoration is an ancient untested healing process and form of suspended animation that appears in The Legend of Zelda: Breath of the Wild. The process was used on the Hylian Champion Link after he was taken to the Shrine of Resurrection an old Sheikah medical facility after he was injured defending himself and Princess Zelda from corrupted Guardians at Fort Hateno during the Great Calamity.

Background & History
The Slumber of Restoration is an ancient healing process developed by the ancient Sheikah who created the Shrine of Resurrection ten thousand years before the events of Breath of the Wild. The Shrine of Resurrection was an elaborate medical facility constructed by ancient Sheikah, along with the other Shrines, the guardians and the Divine Beasts, as a means of sustaining their most formidable warriors. After Calamity Ganon was defeated by an incarnation of the Princess of Hyrule and the Hero chosen by the Master Sword with the aid of an army of Guardians and the Divine Beasts, the Sheikah were forced to bury it along with the rest of their technology after the Sheikah became pariahs in Hyrule due to fears of their technology being a threat to the Kingdom.

100 years before Breath of the Wild, Princess Zelda and a team of Sheikah researchers found the Shrine on the Great Plateau and began researching it to learn its purpose. Unlike the other Shrines, Zelda and her team were able to enter the facility and as a result became a source of immense study for her and her Sheikah allies. They discovered its purpose as a medical facility and confirmed it had been created by the Ancient Sheikah.

Zelda speculated in her research notes that such a facility was made as part of the clan's efforts to destroy Calamity Ganon during their first war against the villain ten thousand years ago, instilling a sense of dread within the young princess, who feared just how powerful Ganon truly was to necessitate the need of such a facility.

Great Calamity
Knowing Ganon would return due to a recent prophecy, Zelda and the Sheikah repaired the Shrine of Resurrection, but did not have time to properly test the Slumber of Restoration out before Ganon returned, seized control of the guardians and the Divine Beasts, and laid waste to the kingdom of Hyrule. However as Link was severely injured battling Guardians, Zelda and her Sheikah allies were forced to use the untested process on Link to save his life. Though it was untested, Zelda and her allies where aware of the possibility that it would rob Link of his memories, thus Zelda had Purah leave her Sheikah Slate in the Slumber of Restoration chamber inside the Shrine, which would help guide Link when he finally awoke should their fears prove true. However they where unaware how long it would take for Link to heal and awaken from his suspended animation, which lasted one hundred years and left Link in a weakened and amnestic state. While Link slept in the shrine for one hundred years, his injuries healed while he bathed in a healing liquid which apparently provided him with nourishment and halted his aging, as he is shown to have not aged at all in one hundred years and despite his amnesia and weakened state is in reasonably good health when he awakens.

Link's Awakening
One hundred years after the Great Calamity, Link is awaken by the telepathic call of Princess Zelda who begs him to awaken as Calamity Ganon had slowly been building up his strength to rebuild his body by siphoning Zelda's holy power as she kept him under seal and she realizes that he must be defeated soon or she will no longer be able to contain him. Thanks to the Slumber of Restoration, Link recovers from his injuries and awakens to begin his journey to reclaim his memories, the Master Sword, free the Divine Beasts, and defeat Ganon to free Princess Zelda and restore the Kingdom of Hyrule. Though amnestic, Link instinctively follows Zelda's telepathic instructions and uses the Sheikah Slate to leave the Shrine and activate the Sheikah Tower on the Great Plateau which activate other towers and shrines across Hyrule.

The weakened state it left Link in made him so weak that he didn't have the strength to remove the Master Sword from its pedestal (despite the fact that Link had been chosen by the blade and was able to wield it one hundred years prior) in Korok Forest let alone confront Ganon which many of Link's allies warn him against attempting in his current state, though thanks to the spirit of Zelda's father King Rhoam Bosphoramus Hyrule disguised as an old woodcutter living alone on the Plateau had been secretly watching over Link and guided him after he woke up to the four shrines on the Plateau which contained Runes and trials which would aid on his quest and would prove key in helping Link grow strong enough to pull the Master Sword from its pedestal in Korok Forest as well as make him strong enough to free the Divine Beasts and ultimately defeat Ganon.

Recovered Memories & Strength
After leaving the Plateau, Link meets the elderly Impa in Kakariko Village and she is disheartened to learn that Link has no memory of her though is patient with him and gives him time to prepare himself to hear Zelda's message to Free the Divine Beasts and explains to him Calamity Ganon and the Divine Beasts' history. She tells him to seek out Purah who helps Link restore the missing and corrupted components of his Sheikah Slate, restoring pictures that Zelda had taken one hundred years earlier which Impa and Purah discover are key to restoring Link's memories. Link also learns that he was placed in the Shrine by Purah and her subordinate Robbie, who along with Impa decided to split up in order to ensure one of them would survive long enough to aid Link after he awoke from the Slumber of Restoration. Impa, Purah, and Robbie all survive the Great Calamity and all are still alive one hundred years later to aid Link in his quest.

Eventually, Link discovers the Master Sword under the protection of the Great Deku Tree in Korok Forest who reveals he is free to take the sword however he reveals that it will test Link to ensure he is strong enough to wield it. If Link tries to remove it in his weakened state it will sap all his hearts killing him, thus Link must increase his strength by obtaining Heart Containers which he can obtain by trading Spirit Orbs obtained from completing Shrine trials, exchanging Stamina Vessels for Heart Containers via Horned Statue, or freeing the Divine Beasts. Once he has at least 13 hearts (yellow extra hearts do not count to this total) he will be strong enough to claim the Master Sword. Link can obtain the Master Sword as soon as he leaves the Plateau has acquired 13 hearts and found his way through the Lost Woods to reach the Master Sword's pedestal in Korok Forest, thus can obtain it early on provided he collects enough Spirit Orbs to trade for Heart Containers.