Little is known about Tyrah. She is a scientist, possibly a mad one. The only thing for sure is that she is positively dangerous with crystals in her hands.
At least parts of Tyrah's Island are her own creations. She terraformed the shattered caverns, accidentally created the Rock Monsters while trying to make pet rocks, destroyed her ship near Dark Moon Bay with an inadvertent crystal mixture, and planted the forest at Whisper Hollow. She also built the workshops, flare cannons, Sunspire and other structures.