Mari San Tekka is a Force-sensitive hyperspace prospector of the San Tekka clan — the same family that, thousands of years later, produces Lor San Tekka in The Force Awakens. From the age of six she could locate Paths, unconventional routes through hyperspace that nobody else can plot.
The Ro family took her, and by the time of Light of the Jedi she has been alive for over a century, housed in a medical pod aboard Marchion Ro's flagship Gaze Electric, still generating the routes that let the Nihil appear anywhere and vanish. She dies in 231 BBY. Her captivity is the single fact that explains why the Republic cannot catch them, and the era is careful to make it an atrocity rather than a gadget.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.