The Garden of Tranquil Souls, known alternatively as the Royal Family Graveyard, serves as the burial grounds for deceased members of the Fire Nation Royal Family as well as high-ranking members of the Fire Lord's court. The grounds can only be accessed using a secret passageway located one a roof of the Fire Nation Royal Palace.
The Garden of Tranquil Souls was constructed during the early days of the Fire Nation and served as the burial grounds for the first Fire Lord's royal adviser. Over the next several centuries, the graveyard became the primary burial grounds for members of the Fire Nation Royal Family as well as high-ranking officials of the Fire Lord's court.
As a child, Azula often disappeared to the Garden of Tranquil Souls to evade Mai and Ty Lee during games of hide-and-seek. The graveyard's seclusion and relative obscurity from public knowledge prompted Azula to use the grounds many years later as the Fire Warriors' base of operations shortly after the end of the Hundred Year War. After enlisting Ukano's help, Azula and the other Fire Warriors began to abduct children from the Fire Nation Capital and subsequently held them captive inside one of the crypts.
Fire Lord Zuko, Avatar Aang, Mai, and Kei Lo eventually unearthed Azula's operations and discovered the Fire Warriors stationed at the Garden of Tranquil Souls, after Ty Lee led them to the secret passageway that she remembered from childhood. Shortly thereafter, the group was ambushed by the Fire Warriors, whom the group eventually managed to subdue.
During the altercation, Mai confronted Azula regarding the whereabouts of the missing children, prompting the latter to attack. Kei Lo intervened in the battle and was subsequently struck by Azula's lightning, causing Zuko to urge his sister to leave Mai and Kei Lo alone. Unfazed, Azula retreated to the crypt of the first Fire Lord's royal adviser, where Zuko pursued her and subsequently engaged her in a battle. While Zuko pursued Azula, the rest of the group entered a nearby crypt in which they found the missing children with Ukano, managing to defeat the Fire Warriors who were guarding the cell in order to save the prisoners.
Even after being subdued by Azula, Zuko remarked that she would never be Fire Lord, prompting Azula to reveal that it was no longer her intention to usurp the throne. She revealed that it was her destiny to shape Zuko into her likeness and highlighted how she was able to unearth his capacity for ruthlessness, before disappearing in a cloud of smoke.
The Garden of Tranquil Souls is a vast expanse of clear land lined with numerous graves and elaborate crypts. It can only be accessed using a secret passageway located near the Fire Nation Royal Palace. The burial grounds are surrounded by coniferous trees, with mountains visible beyond the groves. The graveyard retains an ominous aura due to a persistent layer of fog surrounding the grounds.
While the gravestones differ in size and height, they all resemble a rounded rectangular obelisk protruding upward from a dome-shaped base. There is no clear pattern regarding the placement of gravestones, given that spacing between graves is inconsistent and graves are oriented in different directions. Certain deceased individuals are housed within elaborate tombs, such as the first Fire Lord's royal adviser, whose crypt is shaped in the likeness of a lion turtle. The graveyard shows little evidence of regular upkeep, given that the majority of headstones are either fragmented, covered by vines, or surrounded by moss.