The Black Tower, originally known as Ambi's Tower, is the final dungeon in The Legend of Zelda: Oracle of Ages. This massive tower is situated near the heart of Labrynna, southwest of Lynna City. The tower plays an important role in the game's story, as Veran's plans revolve around its construction.
The Black Tower was built four hundred years prior to the time of Oracle of Ages, by the order of the country's then-reigning monarch, Queen Ambi. Ambi ordered the tower's construction, intending it to be a beacon to guide her lost lover, a pirate captain, home from the sea. Its construction was apparently halted for unknown reasons.
In the present day, Veran, Sorceress of Shadows and an agent of Koume and Kotake, possesses the body of Nayru, the Oracle of Ages. Using the oracle's powers, Veran travels back in time four hundred years and manages to worm her way into Queen Ambi's favor and becomes the queen's advisor. She uses Nayru's control over time to create the Endless Day and inveigles Ambi into forcing the townsfolk to slave away unceasingly on the tower's construction. The people of Labrynna, bitter from the way Ambi now represses them, begin calling the tower, then known as Ambi's Tower, the "Black Tower." The effects of Veran's actions can be seen even in the present time, as townspeople will note that they think that the Black Tower is spontaneously growing taller.
Link later confronts Veran and saves Nayru, but Veran possesses Queen Ambi. Upon the tower's completion, Veran, in Ambi's body, climbs to the top of the tower and calls upon the powers of darkness, granting her even greater power. From the tower's roof, she wreaks havoc upon the country below her, filling the hearts of the country's people with grief and fulfilling Twinrova's orders. Link, with all eight Essences of Time and the Maku Seed in hand, climbs the tower and confronts Veran. After a lengthy struggle, Ambi is saved, the sorceress is destroyed, and her curses are lifted. Nevertheless, the events surrounding the Black Tower's construction have scarred the people of Labrynna and Veran has succeeded in lighting the Flame of Sorrow.
Though Link is allowed to enter the Black Tower at any time during his quest, the tower is never treated as a mandatory dungeon until the end of the game, when he enters it to confront Veran. He is, however, required to enter it during his first trip into Labrynna's past. During this visit, he is told about the tower's history and is given a Shovel. At this point, the area of the tower he is allowed to explore is limited to the first floor. Later in the game, more floors are made accessible and enemies begin to appear throughout the structure. When the tower is completed, it is split into two parts: the main tower, consisting of three nearly-identical floors, and the turret, consisting of a maze of staircases, which spans four floors, and the roof. The turret, however, is inaccessible until Link obtains the Maku Seed from the Maku Tree.
After clearing the Moonlit Grotto in a Linked Game, Impa calls Link to the tower in the present day. It turns out that Vire has kidnapped Princess Zelda and taken her to the Black Tower. Link must climb the tower while jumping over fireballs with the Roc's Feather in a side-scrolling segment highly reminiscent of the arcade game Donkey Kong. As a reward for rescuing her, Zelda will give Link a Seed Ring which, when appraised, will turn out to be the Blue Joy Ring.