Kosa-Yin Hadu

During the twilight of the Galactic Republic, the Force-sensitive male Gungan Kosa-Yin Hadu became a member of the Jedi Order. He became a Jedi Padawan, training under the guidance of Jedi Knight Kin-Ya Dosun, another Gungan. As a Padawan, Hadu constructed his own lightsaber and focused his training on becoming a Jedi Guardian, a specialized branch within the Jedi Order emphasizing the development of combat skills. Around 33 BBY, Hadu and Dosun received a mission from the Jedi Temple situated on the planet of Coruscant, but they subsequently disappeared. Hadu eventually fell to the dark side of the Force, becoming a Dark Jedi. He ultimately joined the Believers, a Sith cult operating from a Sith fortress on the planet Almas, located within the Cularin system. At some point, the Gungan imbued the focusing crystals within his lightsaber with dark side energy, causing the crystals to channel potent dark side power into anyone who wielded the weapon.

In approximately 31 BBY, Garvin Delquist, who led the Believers, instructed Hadu and the Mon Calamari Dark Jedi Gar Granga to kill the kaluthin plants on Almas. These kaluthin, created millennia prior by the Sith Lord Darth Rivan to make Almas habitable, were targeted because Delquist believed their destruction would help the Believers drive the Jedi Order away from Almas, where the Order maintained a training facility. Hadu and Granga established a temporary camp on a hilltop on Almas, erecting a tent that served as Hadu's field office and living quarters. From this base, the Believers launched attacks on kaluthin farms across Almas over a period of three months, poisoning numerous aquifers with a biological toxin and causing extensive kaluthin die-offs. Angered by these attacks, some kaluthin farmers on Almas wrongly blamed the Jedi Order for the destruction of their crops. To further exacerbate tensions between the farmers and the Jedi, Hadu visited the cantina Building 49-A in the city of Forard and spoke negatively about the Jedi in the presence of several farmers.

Scientists at a kaluthin research station on Almas began investigating the areas of kaluthin extinction. Hadu and Grangra, fearing that the station posed a threat to the Believers' operation, believed the researchers might identify the toxins they were using. To counter this threat, Hadu, Granga, and other Believers traveled to Cularin to disrupt a shipment of supplies destined for the research station, preventing the scientists from continuing their studies. These supplies were scheduled to be transported to Almas by the Duros Welrin Maduk aboard the freighter Fool's Paradise. The two Dark Jedi, along with other Believers, went to the Fool's Paradise's landing bay in Hedrett to hijack the vessel. As a precaution, Hadu and Granga parked a starship near the Fool's Paradise and used a Force illusion to conceal both their craft and an exit from the landing bay. Accompanied by a squad of battle droids and three other Believers, they approached the Fool's Paradise and told Welrin Maduk they were sent by the port authority. When Maduk protested, claiming his ship had already been inspected, Hadu and Granga activated their lightsabers, preparing to attack. However, the Heroes of Cularin, a group of independent agents operating in the Cularin system, intervened to rescue Maduk. As the agents approached, Hadu and Granga fled through the concealed hangar entrance, leaving the droids and other Believers to face the agents.

Upon returning to the Believers' camp on Almas, Hadu received a holographic message from Garvin Delquist, who informed him and Granga that the Jedi had discovered their presence and urged them to hasten their poisoning of the kaluthin. The Heroes of Cularin investigated the aquifer poisoning and launched an attack on the Believers' camp. Alerted to the attack, Hadu emerged from his tent and engaged the agents in combat alongside his guards, while the other Believers prepared their landspeeders for evacuation. The agents ultimately defeated Hadu and his Believer subordinates, thwarting the Gungan's attempts to destroy the kaluthin. After learning Hadu's identity, Jedi Master Seenlu Kir began researching the mission on which Hadu and Kin-Ya Dosun had disappeared, hoping to uncover the circumstances of their loss. Despite her efforts, she gained no new information about the two Gungans.

Kosa-Yin Hadu possessed a volatile temper and readily engaged in persecution and torture to achieve his objectives. Despite his initial training as a Jedi Padawan, he later shifted his allegiance to the Believers, a Sith cult.

He wore an All-Temperature Cloak and carried both a lightsaber and a heavy blaster pistol.

Hadu had mastered various Force powers, allowing him to sense things, manipulate objects telekinetically, heal, enhance his focus, and improve his fighting abilities. He could also utilize Force hatred and Force rage in combat. Additionally, Hadu was multi-lingual, capable of speaking Gungan and Mon Calamarian in addition to Galactic Basic Standard.

Adam Burns created Kosa-Yin Hadu for The Kaluthin Are Always Greener, a 2002 role-playing supplement within the Almas, Sweet Almas trilogy of the Living Force campaign. In this supplement, players assume the roles of the Heroes of Cularin. During their confrontation with Hadu at the Believers' camp, the Gungan's combat effectiveness varies based on the players' role-playing experience level. At lower tiers, Hadu is weakened due to expending significant Force energy earlier in the day to terrorize farmers, and he refrains from using the Force to heal himself during combat, considering the agents unworthy of the effort. In the medium tier, Hadu has used some Force energy to intimidate innocent beings prior to the assault, and he considers using the Force to heal if the players pose a significant threat. At higher tiers, Hadu is at full strength during the encounter. The battle against Hadu can conclude with either his death or escape. If the agents kill him, one of them may be able to loot his lightsaber.