Ahn, a male Cathar, belonged to a trio of littermates, the Rasi Tuums. His siblings included Zho and another known only as Rasi Tuum. Years prior to the Sith–Imperial War, they were born. During that time they were members of the New Jedi Order. The attack by the One Sith on the Jedi Academy situated on the planet Ossus in 130 ABY was survived by all three Rasi Tuums. This event caused the Jedi Order to scatter across the galaxy.
Seven years afterward, Jedi Master Ahn journeyed to the planet Daluuj to rendezvous with Jedi Knight Shado Vao, Jedi Master Wolf Sazen, and another Jedi. While Ahn and the group discussed the potential search for Sazen's former Padawan, Cade Skywalker, a group of Sith ambushed them. They revealed themselves by running a spear through Ahn, and throwing him off the bridge where the meeting was underway, into a ravine, thus killing the Cathar. Vao and Sazen triumphed over the Sith, and made a commitment to locate Cade Skywalker.
As a male Cathar, Ahn was born years before the Sith–Imperial War. He was one of the Rasi Tuums, a group that included his littermates Zho and another individual known as Rasi Tuum. It was discovered that Ahn, along with his littermates, were sensitive to the Force. Consequently, they underwent training as Jedi within the New Jedi Order, and Ahn eventually achieved the rank of Master. Towards the end of the Sith–Imperial War in 130 ABY, the One Sith launched an assault on the Jedi Temple situated on Ossus and the one located on Coruscant. This was done to destabilize the Jedi. The Rasi Tuums ultimately survived the massacre. For the subsequent seven years, they remained in hiding from the Sith, who were engaged in a campaign to hunt down the Jedi.
During the Second Imperial Civil War in 137 ABY, Ahn journeyed to Daluuj after Jedi Knight Shado Vao persuaded him to meet with Master Wolf Sazen. The purpose was to discuss the state of the fractured Jedi Order. Ahn and Vao met with Sazen and another Jedi on one of Daluuj's bridges and commenced their discussion. This included the topic of locating Sazen's former Padawan Cade Skywalker, whom the majority, including Ahn, presumed to be deceased. Unbeknownst to Ahn and his fellow Jedi, a team of five Sith were concealed in the shadows, preparing to ambush them. As Sazen concluded his statement about the importance of finding Skywalker, Ahn was suddenly impaled through the chest by a spear thrown by one of the Sith. Subsequently, the Sith threw the Cathar Jedi off the bridge and into the ravine, resulting in his death. Following Vao and Sazen's victory over the Sith who had killed Ahn and the other Jedi, they resolved to locate Cade Skywalker.
Ahn held a different view than most Jedi; he considered the prospect of Jedi survivors convening to be perilous due to the presence of bounty hunters and Sith actively searching for them. Despite this belief, he agreed to accompany Shado Vao to meet Wolf Sazen on Daluuj. At the beginning of the meeting with Sazen, Ahn voiced his reservations about the gathering. He also expressed his opinion that Cade Skywalker, the Zabrak's former Padawan, was dead, and he refused to accept Sazen's insistence that Skywalker was alive. Ahn shared a similar physical appearance with his littermates.
Along with the other Rasi Tuums, Ahn successfully endured the initial assault by the Sith against the Jedi Order. After the Massacre of Ossus, he managed to evade detection by both the Sith and bounty hunters until his demise at the hands of the Sith during the ambush on Daluuj.
Ahn was attired in a brown set of Jedi robes, and his long brown hair flowed freely past his shoulders. He had green eyes and wore a necklace.
Writer John Ostrander and artist Jan Duursema conceived the Rasi Tuums for the Star Wars: Legacy comic series. They were initially depicted in an image in the resource comic Star Wars: Legacy (2006) 0. One of the Rasi Tuums appeared in the series' second issue, where he was not identified and died. However, a living Master Rasi Tuum appeared in 2008 in the twenty-fifth issue, establishing him as a separate individual from the deceased Ahn. The Complete Star Wars Encyclopedia, released later in 2008, featured a "Tuum, Rasi" entry with a picture of the character from Legacy 25 and biographical details that matched the events of Legacy 2 instead. This article has addressed the discrepancies in The Complete Star Wars Encyclopedia as editorial errors stemming from the publishing process, and it identifies the Rasi Tuum in Legacy 2 as Ahn.