Kasuto

Kasuto is the name of two towns in The Adventure of Link, Old Kasuto and the Hidden Town of Kasuto.

Old Kasuto
The original town of Kasuto was attacked and destroyed by monstrous Moas, forcing its people to flee, although one Old Man stayed behind. Upon Link's first arrival to Old Kasuto, the Moas who have taken over the town are invisible to him, and only by possessing the Cross can the young hero see these flying creatures. The Old Man who is left here informs Link that the town is deserted, and that he must look in the woods to the east in order to find the new village of Kasuto. Once Link has obtained all of the eight Magic Containers in the game, the Old Man of Old Kasuto will reward him with his most powerful magic yet, the Thunder magic. Link can also find a hint on the location of the Magical Key written on a wall in one of the empty houses.

Hidden Town of Kasuto
The Hidden Town of Kasuto, also known as the New Kasuto, is found in the eastern woods of the area and is revealed upon hitting a patch of grass with the hammer. One of the elderly women living here approaches Link and, if the young hero has three out of the four Magic Containers, she will invite him inside her house to claim the fourth and last Container. Once again, Link can find a hint written on a wall in one of the empty houses which reveals the location of a Heart Container near the shore of Three Eye Rock.

On the second area of the town is a house with its door wide open. The chimney inside the house has an entrance to it, and entering it leads Link to an Old Man who teaches him the Spell. Using this new-found spell at the edge of town causes a temple to rise from the ground which houses the Magical Key.

Theory

 * It is often noted that Kasuto is the only town name in The Adventure of Link that does not have a similarly named character in Ocarina of Time. This, combined with unused data found by hacking the Ocarina of Time game cartridge, has led to speculation that another sage with the name of Kasuto may have at one point been intended for the game.
 * Kasuto and Old Kasuto may have served as a prototype or concept for Kakariko Village and the Hidden Village. In addition to the names' similarity between Kasuto and Kakariko Villages (first and last syllabes), Old Kasuto shares a connection with the Hidden Village that appears in Twilight Princess, which is also ghost town with a single resident.

Trivia

 * The original Japanese text written on the wall in Old Kasuto reads: ""
 * The original Japanese text written on the wall in Hidden Kasuto is a text-puzzle. Japanese text can be read from left to right or from top to bottom. All of the text in the game expects the reader to read from left to right like you would in regular english. However, when reading the text on the wall from left to right then you will get nothing but nonsense. Once you start reading it top to bottom, you will get the hint.
 * This town features one of the rare occasions where Link is known to speak; the others being when Link finds the mirror in the Water Town of Saria and Phantom Hourglass (when calling out to Astrid and a young Goron on Goron Island). When trying to enter the chimney, Link says, "LOOKS LIKE I CAN GET IN THE FIREPLACE." Although, like with the mirror, this could be the result of the English translation since the Japanese text doesn't use a first-person pronoun in both cases.