In 55 BG, Avatar Roku remained on this island for five months for spiritual training with Fire Sage Kaja to try to master the Avatar State. However, instead of listening to Kaja's teaching, an impatient Roku triggered the Avatar State by using the winter solstice sun, which resulted in the destruction of the upper half of the temple and the eruption of the nearby volcano on the island.
Team Avatar visited the island in 99 AG after Avatar Roku's dragon, Fang, told Aang to come there to contact Roku. There, at the island's temple, the fire Avatar told his young successor about the impending arrival of Sozin's Comet and subsequently destroyed the building with lavabending in an effort to expel the Fire Nation soldiers that had invaded the island. After this, the lava never stopped flowing and the island became uninhabited.
Several months later, Aang washed ashore on the island after having braved a storm and his friends found him there lying unconsciously on the beach. After his broken glider staff washed ashore as well, Aang let the lava of the island consume the object that would otherwise reveal his identity as the Avatar while traversing the Fire Nation and left with his friends to continue their journey to defeat the Fire Lord.
- Main article: Fire Temple
The Fire Temple, built on the island so that it aligned with the solstices and equinoxes, was a five-tiered pagoda that sat on a hill near the volcano's base, managed by a small group of Fire Sages. After Avatar Roku destroyed the temple in 55 BG, he rebuilt it and it was here that he perfected his use of the Avatar State. After his death, the temple was rededicated to him. The ancient temple used mechanisms that required firebending to operate. The temple was destroyed again when Aang channeled Roku's spirit to face the threat awaiting him at the Fire Temple directly following the winter solstice.
The sanctuary was built to receive a shaft of sunlight through a giant ruby at sundown on the winter solstice. Avatar Roku meditated in this sanctuary with Fire Sage Kaja to learn to master the Avatar State, and it was here that Roku becomes stuck in the Avatar State while using the spiritual energy from the sun during the winter solstice.
At the time of the winter solstice, the light from the ruby illuminated the statue of Avatar Roku, making it possible to communicate with him. When Avatar Roku was alive, the previous generations of sages used the sanctuary to communicate with him on the solstice, but now only the Avatar can communicate with Avatar Roku. The sanctuary doors protected the sanctuary from intruders; they could only be opened by either a fully realized Avatar or five simultaneous fire blasts.