Before humans evolved, the Nilai-Kanai ruled the earth, with their monarchy inhabiting the South-Pacific temple. In order to control the pollution their luxuriant civilization created, the Nilai-Kanai created Dagahra, who consumed the pollution and cleansed the waters. Unfortunately, something went wrong, and Dagahra became uncontrollable, spawning thousands of Barems and killing off all but a few of the Atlanteans, who continued to live in the temple.
After Mothra Leo came to the temple to fend off Dagahra, who had become reawakened and sought out the temple, it was revealed that Princess Yuna, a former ruler of the Nilai-Kanai projected as a hologram inside the temple, knew where the Nilai-Kanai treasure, Ghogo, lay. While the Elias and a group of Japanese kids searched the temple and its grounds, Yuna commanded the temple's Guardian Towers to fight off Dagahra, as Mothra Leo was injured and being poisoned by the Barem.
Later, after Mothra Leo had transformed twice, first into Rainbow Mothra and then into Aqua Mothra after Ghogo sacrificed itself to revive him, he managed to defeat Dagahra. Yuna then levitated the monster over the temple, and dropped it, destroying Dagahra and causing the temple to collapse deep beneath the waves.