Tho'natu, a male Twi'lek Jedi, served the Jedi Order as a Jedi Knight during the concluding period of the New Sith Wars. He participated in the Ruusan campaign. By 990 BBY, he had been promoted to Jedi Master. In that year, the Order received a message indicating that a wounded Sith Lord was located on the planet Ambria. Consequently, Tho'natu led a team of thirteen Jedi to apprehend the Dark Lord. Upon their arrival, they faced an attack from Darovit, a former Padawan, whom Tho'natu and his team swiftly killed, under the mistaken belief that he was the Sith Lord. However, Darth Zannah had secretly hidden herself and her Master, Darth Bane—the actual Sith Lord mentioned in the message—and had mentally driven Darovit to insanity. Tho'natu and the Jedi team, incorrectly assuming the Sith were eliminated, departed, inadvertently allowing the Sith Order to survive.
During the twilight years of the New Sith Wars, Tho'natu, a Force-sensitive male Twi'lek, dedicated himself to the Jedi Order. As a Jedi Knight, he enlisted in the Army of Light and fought in the Ruusan campaign, the concluding campaign of the conflict. Prior to the Seventh Battle of Ruusan, Tho'natu was reassigned to the Fairwind, a gunship commanded by Jedi Master Valenthyne Farfalla, thus escaping the devastating explosion of a thought bomb, a lethal Force power employed by the Brotherhood of Darkness in a failed attempt to annihilate the Army of Light.
By 990 BBY, a decade following the war, Tho'natu had earned the rank of Jedi Master. That year, a message drone reached the Jedi, revealing the presence of a helpless, severely injured Sith Lord being cared for by a healer named Caleb on the planet Ambria. Recognizing that this must be the Sith Lord previously hunted by Lord Farfalla and four other Jedi on Tython—a mission from which they never returned—the Jedi High Council formed a team under Tho'natu's leadership, comprising five additional Jedi Masters and eight Jedi Knights. Aboard the Jedi cruiser Light of Truth, Tho'natu guided the team to Ambria to apprehend the Sith Lord. Upon landing, Tho'natu and his Jedi team discovered Caleb's brutally mutilated remains outside his hut. As they approached the dwelling, Tho'natu announced their arrival, offering assistance. Suddenly, they were attacked by the deranged former Padawan Darovit, whom Tho'natu and the others quickly defeated.
Tho'natu then entered Caleb's hut, where he discovered five lightsaber hilts, which he believed had been taken as trophies from the five Jedi killed on Tython. Noticing Darovit's missing hand and possession of a golden lightsaber identical to Farfalla's, Tho'natu incorrectly concluded that Darovit was the Sith Lord hunted by Farfalla and the others. He reasoned that Darovit had killed them, sustained severe injuries, and sought help from Caleb after driving himself insane while attempting to heal himself with the dark side. Tho'natu further assumed that Caleb had sent the message to the Jedi, but Darovit discovered this and killed the healer in retaliation. Mistakenly believing the Sith to be finally eradicated from the galaxy, Tho'natu and the Jedi returned to the galactic capital of Coruscant, bringing the stolen lightsabers to be kept in the Jedi Temple, as well as Caleb's remains for a proper funeral. A monument was later erected in the Jedi Temple to commemorate Caleb and the Jedi who perished on Tython.
However, unbeknownst to Tho'natu, Darovit's cousin, the Sith apprentice Darth Zannah, had murdered Caleb and driven Darovit insane to provoke an attack on the Jedi. She had then concealed the presences of herself and her Master, Darth Bane—the true Sith Lord mentioned in the message—hiding within a small trapdoor inside Caleb's hut. As Tho'natu reported the final destruction of the Sith to the Jedi Council upon his return to Coruscant, Zannah's scheme to maintain the secrecy of the Sith Order's survival was accomplished.
Tho'natu's time on Ruusan during the New Sith Wars instilled in him a deep understanding of the threat posed by a Sith Lord. Consequently, he approached the Ambria mission with initial caution. He and his Jedi team were deceived by Zannah's plot to keep the Sith hidden, leading Tho'natu to incorrectly conclude that the Sith had been eliminated.
Tho'natu, a Force-sensitive individual, underwent training in the Jedi arts during the concluding years of the New Sith Wars, achieving the rank of Master by 990 BBY. Tho'natu possessed proficiency in combat, and when dispatched to confront the last known Sith Lord on Ambria, he and his Jedi team effortlessly defeated Darovit.
Drew Karpyshyn conceived Tho'natu for his 2006 novel Darth Bane: Rule of Two, the second book in the Darth Bane Trilogy.