This fire Faerie turned up when the island elders went missing, and originally claimed to be working for Queen Fyora, but it was eventually revealed that she was working with the evil shaman, Tura-Kepek.
Whilst it was originally thought she was devoured by Moltenus, she later appeared in Neopets Puzzle Adventure. In it, she and Tura-Kepek tried to free Moltenus once more. In exchange for helping the shaman, Eithne was promised the fiery remains of Mystery Island. She was eventually defeated, and flew directly into the heart of Techo Mountain. It is unknown if this killed her or not.
No, the incantation is nearly complete!