Crescent Island

Crescent Island is the name of a landmass shaped like the Crescent Moon located to the south-southeast of Labrynna's southern coastline out in the Zora Seas and across the Crescent Strait in Oracle of Ages. The island is not easily accessed and can only be reached by one with a raft, an animal that can navigate the rough seas, or some other means of safely navigating the seas. It is primarily the home of the reptilian Tokay race, who are depicted as a coy, peaceful and yet somewhat opportunistic race (e.g. taking Link's items and forcing him to go through a series of trades to get them back, selling Dimitri the Dodongo in exchange for Ember Seeds, etc). It is implied that the island's location is not a well known fact amongst the public of Labrynna's mainland, as reaching it requires a special Sea Chart. In turn, the Tokay appear not to have much contact if any at all with the outside world outside of trade to stock the sole store on the island, as they don't realize what Link is at first upon his shipwreck arrival on the island.

The Secret Island of the Tokay
The island appears to be first and foremost the home of the Tokay, with no signs of any other races inhabiting or having inhabited the island at any point. The sole source of trade or commerce on the island (and the only place where one can purchase supplies) is the Tokay Shop located on a small landmass at the island's northeastern border in the past and on the eastern shores of the island itself in the present. It is here that Link does much of his trading to get his items back upon his first arrival on the island. Apart from its unique, eponymous shape, Crescent Island has another aesthetically appealing feature: a small peninsula that juts out into the main bay in the past (now largely above sea level in the present) where a strange statue supposedly built by the Tokay resides, which they call their "guardian". The passageway residing within the Tokay Guardian leads to differing places in the past and present ages: in the present, it leads to the Moonlit Grotto, the home of the Echoing Howl, one of the eight Essences of Time; in the past, the passageway can only be opened by one possessing the jewel known as the Tokay Eyeball and would yield safe passage through to the Sea of No Return and subsequently the Ancient Tomb.

As it would appear, the island appears to be drifting eastward, slowly but surely, with the passing of time. This can be seen by Link, who travels back and forth 400 years between the past and present with the assistance of the Harp of Ages. Another notable change over the centuries, as with the rest of Labrynna's southern borders, more land is uncovered for the island as the Zora Seas receded a bit over the centuries. This could account for the disappearance of the Sea of No Return as well as the transformation of the secret passageway leading to it becoming the Moonlit Grotto as the terrain was transformed with the receding of the ocean. The island is also home to a special tree nursery said to have housed a special Scent Tree long in the past before it was blown over by a great storm. This changed however when Link arrived on the island and planted a small Scent Seedling he'd won in a Tokay game in the nursery and revisited the site in the present, discovering it to have grown into a full-fledged Scent Tree nearly identical to the original. There also exists a winding maze beneath the island in the present age that is blocked off by the Sea of No Return in the past age.

Crescent Strait
Crescent Strait is a small body of water which surrounds Crescent Island in both past and present ages. In the present, one who can dive down deep enough can see a huge underground maze, which leads to a hidden treasure, as well as the whirlpools which ravage the Zora Seas. It was once neighbor to the Sea of No Return, which has since vanished mysteriously. The Crescent Strait largely separates Crescent Island from the southern borders of Labrynna's mainland and can only be navigated by sea-faring means.

Trivia

 * An island with a similar name, Crescent Moon Island, appears in The Wind Waker.