Tower of Spirits

"With their remaining power, they buried the Demon King's spirit in the ground. They built shackles to imprison him, and a tower that acted as a lock. These shackles cover the land to this day."

- Spirit Tracks prologue

The Tower of Spirits is a towering fortress that appears as the central dungeon within Spirit Tracks. The Tower of Spirits is very similar to the Temple of the Ocean King which appeared in Phantom Hourglass in that the player must revisit it each time they complete a dungeon to proceed further and open up a new area to explore. However, unlike its predecessor, there is a staircase that allows Link to skip over previously completed floors. Each floor of the tower has puzzles required to proceed to the next. The structure was built by the power of the legendary Spirits of Good and serves as the lock on the prison of the Demon King Malladus, who can only be freed from his prison at the top of the tower using the Altar of the Demon King that resides in the topmost chamber of the tower. Anjean, an ancient Lokomo servant of the spirits, serves as the sage of the tower with the primary duty of guarding the tower from evil. Phantoms also serve as guards of the tower to ward off evil ones hoping to reach the top, though they are corrupted to the side of evil by Cole, who seeks to release Malladus from his prison during the events of the game.

Background
The Tower of Spirits has a long history dating back to the days prior to the re-establishment of the kingdom of Hyrule. It is said that in this land's early days, its first settlers lived in peace and prosperity under the protection of the great Spirits of Good that watched over the entire realm. However, about a century before the events of Spirit Tracks, there came a day that this peace was shattered by the coming of a great evil, the Demon King known as Malladus. The Demon King was an extremely powerful entity that destroyed anything in his path as he sought to reduce the world to ruin and bring it to its knees to establish total domination over the world. He was engaged by the Spirits of Good in a long and bloody conflict that resulted in much carnage and loss and seemed to have no end in sight as they attempted to use all of their might to slay the Demon King and save the world from his reign of terror. However, they soon realized they did not possess the strength to truly kill him, thus necessitating a different means of halting his invasion of the land.

The spirits decided that all they could do would be to lock him away where he could do no further harm to the world, and to this end they drove his spirit deep into an underground prison. To seal this prison, they constructed an elaborate set of shackles that spanned in four directions all across the land that would come to be known in time as the Spirit Tracks, as well as a great tower that would act as the lock on his prison, a tower that would eventually come to be known as the Tower of Spirits. This tower, residing at the very heart of the land, was powered by magical energy flowing into it from four special temples across the land by means of the Spirit Tracks. As long as the tracks and the tower remained untainted, Malladus could not re-emerge from his prison and attack the land again. Though this great effort exhausted the spirits' powers, they were able to bring the bloody conflict to a successful end and restore peace to the land. With their power depleted, the spirits decided to return to the heavens, giving the land over to the Hyrulean settlers led by the Hero of Winds and Tetra, who christened it as the reborn kingdom of Hyrule, and leaving their servants, the Lokomo, to protect the land in their stead and protect it from the return of the Demon King.

Appearances
Only once has the Tower of Spirits appeared within the Legend of Zelda series thus far, in Spirit Tracks, where it is without a doubt the most visible and one of the most imposing structures found throughout Hyrule.

Spirit Tracks
Spirit Tracks begins roughly a century after the kingdom of Hyrule was reinstated in the land of the Spirits of Good following the end of the Spirit War. The Spirit Tracks have disturbingly began to vanish all across the land of Hyrule, causing the seal on the Demon King's prison to weaken as a result. This does not go unnoticed by the kingdom's matriarch, Princess Zelda, who suspects that one of her subordinates, the kingdom's chancellor known as Cole, is somehow connected to the disappearance of the tracks due to his questionable and foreboding demeanor. To this end, the princess hopes to slip out of Hyrule Castle without Cole's knowledge in order to visit the Tower of Spirits and discover what has happened to the Spirit Tracks from the sage said to reside there. Cole does not wish for Zelda to visit the tower and meddle with his plans, and thus forbids her from leaving the castle due to "security concerns".

On the day of a graduation ceremony for the newest Royal Engineer, Link, Zelda conducts the ceremony over the protests of Chancellor Cole and secretly slips Link a note during the ceremony asking him to come to her private quarters and warning him to beware of Cole. Link is able to use the directions in the note to locate Zelda's quarters and meets with her there, where she requests him to sneak her out of the castle and take her aboard his train to the Tower of Spirits after telling him of her suspicions regarding Cole involving the disappearance of the Spirit Tracks. Link agrees to this plan and, with the help of the recruit's uniform (the garb of the hero that is now the standard uniform of Hyrule Castle's guards), is successfully able to smuggle Zelda out of the castle through its courtyard. With Link's mentor Alfonzo, the pair board Link's train and set a course for the Tower of Spirits.

When the trio is within sight of the tower however, the portion of the Spirit Tracks they are traveling on suddenly disappears, causing the train to come to an unbalanced and screeching halt in the middle of the field separating Hyrule Castle from the Tower of Spirits. Exiting the train, the trio suddenly look toward the tower and witness a shocking phenomenon: dark clouds begin to circle the summit of the tower, and with a crackle of evil energy that extends down the length of the tower, the structure is suddenly fragmented into five sections, four of which float in a vertical line, reducing the tower to pieces. It is at this moment that Chancellor Cole appears, alongside his henchman Byrne, and reveals his true nature as a monster masquerading as a human as well as his evil plan to revive Malladus. Cole has Byrne knock out Alfonzo and Link while he uses his own dark magic to separate Zelda's spirit from her body. The duo then steal the princess's body and take it to the Tower of Spirits to use as a vessel for Malladus's revival.

Link reunites with Zelda's spirit at Hyrule Castle and takes the secret tunnel leading from the castle to the Tower of Spirits. There they meet Anjean, who sheds light on what is happening. She reveals that the Spirit Tracks have been disappearing because something has happened to the temples that energize the tower. She also states that Zelda's body has been taken to the top of the tower to the Altar of the Demon King, which is now inaccessible due to the shattering of the tower by Cole. Malladus requires a vessel with the blood of the ancient Hyrulean Royal Family flowing through its veins in order to return to his former strength, a revelation that sends Zelda's spirit into great distress as she now realizes what part her body is to play in this plot. Resolving that they must somehow reach the top of the tower and stop the resurrection of Malladus, Anjean tasks the duo with restoring the Spirit Tracks by cleansing the four temples across Hyrule. To reach each of them, she instructs them to retrieve the four stone Rail Maps located within the different sections of the Tower of Spirits, avoiding the corrupted guardians of the tower, the Phantoms along the way. Only by cleansing the temples can these sections of the tower become accessible once more, though they are able to acquire the first in the base of the tower. To reach the temples, Anjean entrusts the pair with the Spirit Train, a locomotive crafted by the power of the spirits whose home is the Tower of Spirits itself. With this strategy, the duo embarks on a quest to restore the tracks and ascend the tower to stop Cole.

Each time the two are successful in cleansing a temple, they return to the tower and are gradually able to climb higher to its upper levels, each time retrieving one of the Rail Maps. Finally, after clearing the Fire Temple, they return to find Anjean missing after the tower is fully restored to its original state and the tracks are restored to each of the different realms of Hyrule. Climbing to the tower's highest levels, the pair face off against Byrne in the stained glass chamber of the tower just beneath the Altar of the Demon King (Zelda having found she can occupy the bodies of Phantoms when struck with a light-infused blade), and though the power-hungry Lokomo that was formerly Anjean's apprentice puts up a powerful fight, Link and Zelda are ultimately able to best him. The beaten Lokomo retreats up the catwalk just outside the stained glass chamber to the Altar of the Demon King at the very top of the tower, where Cole mocks his inability to put down two mere children while completing the resurrection of the Demon King, whose spirit is freed from his prison beneath the altar and infused into Zelda's vacant body floating above the altar. Link and Zelda arrive just moments too late to stop the resurrection of Malladus, who throws Byrne against one of the tower's columns when he foolishly approaches the Demon King demanding power as payment for his role in the demon's resurrection. Cole mocks Byrne's gullibility and flees with Malladus aboard the Demon Train back to the Dark Realm to await the time when Malladus will have fully acclimated to Zelda's body, leaving the stunned heroes gazing after them from atop the tower. Anjean appears and escorts Link and Zelda, alongside the unconscious Byrne, to the lobby of the tower.

After clearing the Sand Temple and retrieving the Bow of Light, Link and Zelda are faced with a new dilemma: locating the entrance to the Dark Realm from which the Demon Train originates. Anjean is at a loss for how to do this, until Byrne reveals that he has come to and has seen the error of his ways. He reveals that, as one of the Lokomo, Cole had him use the power of the spirits to craft a compass that could locate the Demon Train within the Dark Realm, a compass that could not be touched by those with evil hearts known as the Compass of Light. Byrne instructs Link and Zelda to open the way to the uppermost floors of the Tower of Spirits by raising the Altar of the Demon King up to reveal a hidden passageway at the top of the tower using the Bow of Light in order to obtain the compass. The duo triumph once again and acquire the compass from the tower, revealing the tracks leading to the island that acts as the gateway to the Dark Realm just off Hyrule's southwestern coast.

Once Cole and Malladus are defeated, the remaining Lokomos of the land gather and ascend to the heavens to be with their kindred, knowing that with the Demon King's destruction, they are no longer needed. They leave the world under the guardianship of Link and Zelda and all of their descendants. With the departure of the Lokomo and the destruction of Malladus, the purpose of the Tower of Spirits was now fulfilled, and it is presumed that it remained thereafter as a physical reminder of the triumph of good over evil.