When Umbrath turned against Lumeon a thousand years ago, Fuocith combined her magic with that of the other Keepers to lock Umbrath away in a deep sea prison south of Xiro. After that, the four Keepers each created one tribe; Fuocith's being the Fire Tribe. Since then, she is in charge of this tribe's vocation ceremony.
Iris asks Vully and Sirsir about Fuocith after Sirsir reveals that the Halcyon is sailing to Fuocith's Teeth, a port in Zesto. He is also the one who explains to them that Fuocith lives inside a volcano in Zesto, but had already been seen across the entire continent, according to the Elmen at the Teeth. Iris believes that Fuocith can help them find the Plain of Lumeon, and convinces her friends to sail to Zesto.