During the High Republic Era, Hedda Casset was a human female who held the position of captain on the starship known as the Legacy Run. She was the last to serve in that role. By the time the Great Hyperspace Disaster occurred, she had amassed more than forty years of piloting. She was a distinguished veteran of the Malastare-Sullust Joint Task Force before her retirement. After retiring, she became a pilot for the Byne Guild, piloting the Legacy Run. Casset's death happened at the start of the Great Disaster. The Legacy Run was destroyed in hyperspace when Casset attempted to steer it away from an object. Later investigations revealed the object to be a Nihil Stormship using a Path.
The High Republic Era was the time when Hedda Casset lived. In her younger years, she was a member of the Malastare-Sullust Joint Task Force, a regional military organization tasked with safeguarding a sector located around the Mid Rim border. Casset's military journey began with her piloting a single-seat Z-24 Buzzbug starfighter. Eventually, she ascended to the role of commanding officer of a heavy cruiser, recognized as one of the largest starships within the task force's fleet. After dedicating over thirty years to the Mallust JTF, she departed with a distinguished record.
Upon her retirement, Casset accepted a position as a captain of merchant vessels under the Byne Guild. Ultimately, she was appointed as the commanding officer of the Legacy Run, a Class A modular freight transport. Casset managed the freighter with a military approach, ensuring the ship's optimal condition and the crew's disciplined conduct. Her voyages included the transportation of ogrut hides and passengers. Casset was in command of the Legacy Run when it transported a saberfish from Tibrin to Abregado-rae. This required converting half the cargo hold into an aquarium. The countess who ordered the fish had it returned after it fell ill due to her people's inability to care for it. Casset oversaw the return journey as well.
In 232 BBY, the Legacy Run was in the process of transporting a multitude of passengers from the Core Worlds to the Outer Rim Territories. As the starship navigated a well-documented hyperspace route near the Hetzal system, Casset verified the readings before ceding control of the bridge to her second-in-command, Lieutenant Jary Bowman, so she could take her evening constitutional. While walking around the ship, Casset entered a common area and met a young passenger, Serj Ukkarian, who asked her for new holos for him and his friends to watch. Casset told him he had seen everything in the ship's archives. She scolded him for trying to slice into the archives to see age-restricted titles, telling him she knew everything that happened on the Legacy Run. She left after telling the children that they would remember their time aboard fondly once they were doing hard work with their parents off of it.
Casset continued her walk, exchanging greetings with more passengers before finishing her rounds. She went through the passenger compartments, checked on a shipment of liquid Tibanna to ensure it was properly secured, inspected the engines, checked up on the progress of ongoing repairs to the freighter's environmental systems, and made sure there were enough fuel reserves for the rest of the journey. After more than an hour, she went back to the bridge and relieved Bowman of his watch. Immediately upon her return, an alarm sounded. Casset demanded a report. Her navigator, Cadet Kalwar, informed her that there was an object directly ahead in the hyperlane: unknown to the crew of the Legacy Run, it was a Stormship of the Nihil pirate group traversing the Paths, secret hyperspace routes only known to the group and accessible via their Path engines.

Despite her considerable shock at the situation, with only seconds left before impact, Casset ordered her bridge crew to brace themselves before taking direct control of the Legacy Run. She used all of her piloting skill to maneuver her starship past the unknown obstacle, and was successful. However, the Legacy Run, which was more than a century old, could not withstand the stress and broke apart. In her final moments, Casset activated the bulkhead shielding to seal off the cargo modules, hoping to save at least some of the passengers, such as Serj Ukkarian, hoping that the children in the common area had gone to their families due to the alarms. She met Bowman's gaze, and he tried to tell her it had been an honor as they both perished when the bridge ripped open.
The destruction of the Legacy Run triggered the Great Hyperspace Disaster. This resulted in massive amounts of the starship's debris being propelled into the Hetzal system, as well as the near-destruction of the star system due to the liquid Tibanna in its cargo. Casset's final action did save some passengers, including Serj Ukkarian, who had been inside compartment eight, which was halted from a collision with Hetzal Prime's Fruited Moon during the Jedi and Galactic Republic rescue effort.
The disaster's repercussions continued as a series of Emergences of debris, leading to a temporary interdiction on hyperspace travel across large parts of the Outer Rim. Jedi Master Avar Kriss and Jedi Knight Elzar Mann were tasked with leading the investigation into the disaster's cause. They eventually determined that the Legacy Run had been destroyed because Casset had to maneuver it in hyperspace, which was not normally necessary. Ukkarian was a valuable witness. He eventually revealed to Jedi Knight Nib Assek and Padawan Burryaga Agaburry that he had seen "three lightning bolts" while trying to hack into the bridge in retaliation for Casset's earlier scolding. The recovery of the Legacy Run's flight recorder later confirmed the sighting as a Nihil Stormship.
During the dedication ceremony for the new space station Starlight Beacon, Supreme Chancellor Lina Soh memorialized Casset as one of the casualties of the Great Disaster and the subsequent conflicts with the Nihil.
Hedda Casset was an older human woman with grey hair and a body showing its age at the time of her death. Her time in the military had instilled in her a love of discipline and order, which she expected and received from her civilian crew. She further maintained discipline by keeping the aging Legacy Run in top condition, ensuring regular maintenance. She was compassionate, thinking well of the countess from Abregado-rae for bothering to pay to return the saberfish after it became ill, when most nobility probably would not have bothered. Casset also enjoyed talking to children, but she would also be stern with them when necessary, as when she reprimanded Serj Ukkarian for trying to access age-inappropriate media. She was willing to risk her life for others, as when she attempted to save the Legacy Run from a collision.
Hedda Casset was a skilled pilot and military commander. She retired from the Malastare-Sullust Joint Task Force with distinction after more than thirty years of service. At the time of her death, she had more than forty years of flying experience. Her skill was such that she was able to successfully maneuver the Legacy Run, a bulky freighter that moved more like a moon than a starfighter, out of the path of an obstacle, even though the starship's great age meant it did not survive the incident.
Early in her service with the Mallust JTF, Hedda Casset flew an Incom Corporation Z-24 Buzzbug starfighter.
Hedda Casset was a character in the 2021 novel The High Republic: Light of the Jedi, which was written by Charles Soule as part of the Star Wars: The High Republic multimedia project. Her first appearance in an image was in the young readers' book The High Republic: The Great Jedi Rescue. In an early version of the first chapter of Light of the Jedi that was released on IGN, Casset was said to be just over sixty years old. However, this detail was removed in the final version.