This article contains information from The Descenders. As such, it will contain spoilers. Proceed with caution.
Role in the Cade Saga
Role in The Nameless One
When her father, Blatch Helmstoft, moved from Great Glade to the Farrow Ridges, Celestia was three years  old. She grew up in a big mansion hanging from a pine tree that her father had built and her mother introduced her to the healing properties of the flora of the Deepwoods. When her mother became ill, Celestia could nevertheless not help her. The only thing that would have saved her was the shriekroot that was very difficult to obtain for a young girl like her. When Cade arrived at the Farrow Ridges, it was Celestia who cared for him when Thorne Lammergyre brought him after his hut had not survived the first storm. Even if she mockingly called him 'city-boy', she helped him getting used to the harsh life in the Deepwoods. She taught him how to ride prowlgrins, first lending him one of her own, Burrlix, and then gave him a saddle for Rumblix as a present. She asked Cade for help in finding and rescuing her father when he was held captive by the White Trogs in the caves behind Five Falls.
Role in Doombringer
After Phineal told Cade the secret of the Great Blueshell Clam being in the lake, Celestia comes up to him, yet Cade keeps the secret. Celestia then announces that Rumblix has finally grown big enough for Cade to ride him, and helps him fit a saddle on. Then they go on a long ride, including a race to the top of the five falls, and then the Ledges. She then enjoys the party that they throw to welcome Phineal and his brother clam tenders. When they formulate the plan to go to Hive to buy Phraxpistols so they can wage war on the Mire-Pearlers, it is Celestias necklace they sell to get the money to bet on the races. Celestia does not come with them to Hive, yet stays behind to treat the Hammerhead Goblins wounds during the battle, with the help of Tug. Later on, when they return from Hive, she comments on how tug was a natural healer, and proceeds to act as an able medic throughout the battle, saving many lives in the process.
Celestia was very adapted to the life in the Deepwoods, always wore green leather clothes with useful items in the pockets and hanging down from her collar. She loved exploring the Deepwoods and visiting wild tribes like the Hammerhead Goblins, especially with Cade.