Hilde, originally named Hessu was the Mentor Cêpan of Number One and the first of the Keepers to escape Lorien during the Mogadorian invasion. She was the second Cêpan to be killed. She and Number One were killed by the Mogadorians four years after arriving on Earth, in Malaysia.
Hilde is described by Adamus Sutekh while he is in Number One's memories. He noticed "she's in her late fifties, and her face is wrinkled, both with the natural lines of age and the premature weathering of stress. Her gray hair is tightly bound in a stern braid. Her eyes have a hardness to them." It is learned in The Last Days of Lorien that she was the oldest of all the Cêpans aboard the ship.
It is mentioned by the Ghost-One to Adam many times that she was "sort of a drag." She was also described as very athletic and a master of martial arts. She told a young and eager Number One stories of the Loric heroes she helped train. Adam says Hilde was "full of tales of honorable competition, of noble battles fought on Lorien. They're meant to inspire, to demonstrate to One the Loric spirit of perseverance." Sandor described Hilde as shy.