Tokra Hazz, who would later be known as the Hidden One, was a Kel Dor strong in the Force, and a member of the Baran Do Sages. The Baran Do were a Force-based organization located on the planet of Dorin. In the year 19 BBY, the Jedi Order was almost completely destroyed by Order 66 and the subsequent Great Jedi Purge. This led Hazz to believe that the new Galactic Empire would eventually target and destroy the Baran Do as well. To prevent this potential destruction, Hazz made the decision to establish the Hidden Ones, a clandestine group within the Baran Do who would live in a system of caverns under Dorin's surface and whose purpose was to safeguard the Jedi Order's knowledge. He then assumed the role of the group's first leader, adopting the title of the Hidden One. In the year 43.5 ABY, Luke Skywalker, the Jedi Grand Master, along with his son Ben Skywalker, came across the Hidden Ones and their caverns and were told the story of Tokra Hazz by Chara, a member of the secret order.
Tokra Hazz, a Kel Dor with an affinity for the Force, was born on the planet of Dorin. He became a member of the Baran Do, a Force-based organization based on his homeworld, eventually becoming a leading Sage within their ranks. By the time of 19 BBY, he had become a Baran Do Master, coinciding with the near annihilation of the Jedi due to Order 66 and the Great Jedi Purge. With the Empire now ruling the galaxy, Hazz was afraid the Baran Do would meet the same fate as the Jedi Order. Because of this fear, he resolved to create a secret group within the Baran Do, focused on preserving the Jedi's knowledge. His hope was that if the Baran Do were ever destroyed, this secret sect could restore the order.
Hazz ventured deep beneath Dorin's surface, finding a system of caverns. Over years, he painstakingly drilled a long, winding tunnel connecting the surface to the caverns. He then spent even more time expanding and altering the caverns. The Hidden Ones, as the new group was named, was established within these caverns. Hazz became their first leader, adopting the title the Hidden One. To ensure the Hidden Ones' secrecy, Hazz decreed that no one would ever be permitted to leave the caverns. The tunnel he constructed was designed with this rule in mind, making it too long to crawl through and easily collapsible to prevent passage by other means.
In accordance with Hazz's emphasis on secrecy, new members had to accept that they were considered dead to the outside galaxy. To facilitate Sages joining Hazz's new sect, the Baran Do tradition of the dying ceremony was adopted. This ceremony involved a Sage feigning death before secretly traveling to the Caverns of the Hidden One to join the group. Hazz also devised a telepathic method for communicating with the Baran Do on the surface, with the goal of restoring the Sages if they were ever destroyed. By 43.5 ABY, Hazz was no longer in charge of the Hidden Ones.
In 43.5 ABY, Luke Skywalker, the Jedi Grand Master, who had recently been exiled for failing to stop Jacen Solo's, a former Jedi Knight, descent to the dark side of the Force, journeyed to Dorin with his son, Jedi Knight Ben Skywalker, to investigate Solo's fall.
However, Koro Ziil, the Master of the Baran Do, who had previously trained Solo, was not with the Sages at their temple. The Skywalkers eventually located the Hidden Ones, finding their caverns by following Charsae Saal, a senior combat instructor who had adopted the name Chara. This instructor then recounted the story of Tokra Hazz, including the creation of the tunnel and the caverns. The Skywalkers eventually encountered Ziil, who had recently become the leader of the sect and upheld Hazz's rule of prohibiting anyone from leaving the caverns. When Luke eventually confronted and defeated Ziil, the Hidden Ones were disbanded, and the members of the sect returned to the surface.
Tokra Hazz prioritized the advancement of the Baran Do's powers and philosophy above all else. As such, he valued the preservation of knowledge over individual well-being. He was deeply committed to his cause, and the destruction of the Jedi Order instilled in him a paranoia that a similar fate awaited the Baran Do. He feared that all their accumulated wisdom in the ways of the Force would be lost forever. Because Hazz valued knowledge more than life, he chose to establish the Hidden Ones, sacrificing a normal life to safeguard the powers of the Baran Do.
Tokra Hazz received a mention in Fate of the Jedi: Outcast, a 2009 novel by Aaron Allston that served as the first installment in the Fate of the Jedi series.