Heta Kol, also known as Field Marshal Kol, was a Mandalorian female Human. During the third Galactic War, she spearheaded the Hidden Chain, a group of disgruntled Mandalorians, in opposition to Mandalore the Avenger.
In the year 3626 BBY, Heta Kol initiated an attack on the Mandalorian starship named Spirit of Vengeance II. She was joined in this endeavor by Clan Varad, the Dar'manda, and the Ash'ad. As the battle reached its climax, she found herself in direct confrontation with the Alliance Commander and Rass Ordo, ultimately suffering defeat. However, upon receiving news that her forces had successfully secured the banner of Clan Cadera, she strategically withdrew from the conflict.
Following the engagement, Kol convened with representatives from the three factions that had aligned with her, including Tyrus Brokenblade, Bask Sunn, and Durn Wynnward, alongside several members from each respective group. As she observed their bickering, Kol brandished a thermal detonator and hurled it in the direction of Brokenblade. He managed to catch it, preventing its detonation as long as he maintained his grip. Kol asserted that true success hinged on their ability to collaborate effectively. To underscore her point, she stabbed Brokenblade twice, emphasizing their interdependence. Subsequently, she dismissed everyone, instructing them to carry out their assigned tasks.
Some time after Darth Malgus's capture, Heta Kol gathered the Hidden Chain at a secret location, reuniting with Ri'kan Kateen. Ri'kan brought his sister, Sa'har Kateen, a rogue Jedi Padawan, to provide Heta with the necessary assistance for a specific mission.
Knowing that Shae Vizla was pursuing her, Heta intentionally laid misleading trails and eliminated individuals who had outlived their usefulness, making it more challenging for Shae to locate them. Subsequently, Heta assembled the entire Hidden Chain on Ruhnuk, positioning her fleet on standby. Heta exploited Ri'kan's abilities to monitor the various commanders guarding the signal towers and revealed herself when the Alliance Commander was ensnared in a trap using Bask Sunn's sonic disruptors. Although Heta admitted she hadn't anticipated the Commander's presence, her true objective was Shae Vizla. When Shae arrived, Heta suggested a duel to alleviate the boredom of Ruhnuk, providing entertainment for the Hidden Chain, an offer Shae readily accepted, leaving the Commander to Ri'kan.
Upon arriving at the arena filled with members of the Hidden Chain, Heta presented the Clan Cadera banner and disclosed that her parents had participated in the rebellion orchestrated by Jicoln Cadera against Mandalore the Vindicated. This rebellion ultimately failed, transforming the Mandalorians into subservient Imperial servants. She drew a parallel between this situation and Mandalore the Avenger's actions with the Alliance during the War against Zakuul. Heta proclaimed that the Hidden Chain represented true Mandalorians, unbound by loyalty to others and warriors at their core. She then set fire to the Cadera banner, denouncing it as a symbol of treachery and obedience, before challenging Shae to face her.
Heta and Shae confronted each other, receiving Beskar blades from members of Clan Ha'rangir, and commenced their duel. The fighters were evenly matched until Shae was unexpectedly hindered by Bask Sunn's use of a sonic disruptor, unbeknownst to Heta. Heta pressed her advantage relentlessly and nearly defeated Shae. However, Shae overcame her predicament and decisively defeated the Hidden Chain leader in full view of her followers. The duel was interrupted by the arrival of Shae's forces in the arena and the engagement of both fleets. Heta largely remained out of the main conflict and attempted to eliminate a wounded Shae, who still managed to injure Heta. This prompted Heta to escape aboard an Eternal Empire shuttle, with her fleet following her lead.
Upon exiting hyperspace, Heta was disturbed by her defeat at Shae's hands, despite Ri'kan's assertion that their cause was not over, even though the loss of their base and Shae's victory had deepened her wounds. Heta's interest was piqued when Ri'kan, with Sa'har's strong disapproval, mentioned that his sister knew of a powerful weapon that even Darth Malgus coveted, which would aid their cause since Sa'har possessed the key to it. This prompted Heta to ask Sa'har if it was true, and she confirmed it. Heta instructed Ri'kan to ensure that they were not disturbed and departed with Sa'har to discuss the weapon in private.
Heta learned from Sa'har that Darth Nul's holocron contained the schematics for a machine capable of unlocking a person's dormant Force abilities. Heta envisioned the potential of creating a Force-sensitive army to bolster her war efforts, despite Sa'har's insistence that the machine could only reveal their connection to the Force. Heta assumed that Sa'har would be capable of training her new recruits.
Heta Kol later convened a meeting with the Hidden Chain to address the events on Ruhnuk and their impact on the Mandalorian civil war. Heta then revealed that Bask Sunn had betrayed her by using his sonic weapons and declared the Dar'manda as their enemy, stating that Darth Nul's holocron would pave the way for their triumph. Heta concluded the meeting by informing the others that only she and Sa'har would be privy to the complete plan, while the rest would only receive their specific assignments.
Heta Kol's initial appearance was in Star Wars: The Old Republic: Onslaught, as part of "Game Update 6.2: Echoes of Vengeance," which was released in 2020. After the launch of "Game Update 7.0: Legacy of the Sith" on February 15, 2022, players observed changes in both the armor color scheme and the voice actress for Heta Kol. This change coincided with Melissa Medina's announcement on February 17 that she was providing the voice for Heta Kol.