Akku Seii was one of the great masters of the Anzati, training assassins on his homeworld in the decades before the Clone Wars. He was also the teacher of the late Jedi Master Tholme and the contract killer Katichak. During the Clone Wars, Seii's fellow Anzati instructors began training Morgukai warriors for Sora Bulq and the Confederacy of Independent Systems on Saleucami, leaving Seii behind to train the remaining students. The Anzati assassin's code prohibited Akku Seii from telling Tholme about the contract with Bulq when the Jedi Master came to investigate, so they were at an impasse. To settle things, Seii set his students on his former one, who beat them with ease. He subtly pointed Tholme in the right direction by showing him the other master assassins had left.
Akku Seii came from the planet Anzat and, like many members of his species, was trained to become an assassin by a master of Anzati martial arts. He achieved mastery of all forms of combat and thus rose to one of the great masters of the Anzati. It was the tradition of his people that each teacher trained only one student, similar to the masters and padawans of the Old Jedi Order. Akku Seii trained the later contract killer Katichak and the human Tholme. After completing his instruction, Tholme persecuted Katichak for a crime and killed him and would join the Jedi.
During the Clone Wars, Count Dooku was preparing for the final phase of the war. By engaging in protracted sieges on the Outer Rim, the Jedi were supposed to be distracted from the impending attack on the main galactic world of Coruscant. The Morgukai Shadow Army, a combat group made up of clones belonging to the Nikto Warrior Bok, played a central role in his planning and, as a powerful force, was supposed to tie up important resources of the clone army. To train the Shadow Army, Dooku hired Dark Jedi Sora Bulq, the project's coordinator, Anzati instructor, whose job was to train the new clone army in the martial arts of their people's assassins. As the Separatists withdrew numerous masters from Anzat, the few remaining instructors like Akku Seii, who had rejected the separatists' offer, had to train several students at the same time, contrary to the Anzati tradition. The students were trained in the main forms of Anzati martial arts, but have not yet mastered them.
Through Jedi Master Quinlan Vos, Tholme found out that Sora Bulq had visited the planet Anzat. He concluded that Separatist activities were taking place there, so he went there with his former student Aayla Secura to visit his former master. Since he wanted to impress his former teacher, Tholme used the Anzati sneaking technique and approached the meditating Anzati silently until he held his lightsaber up to his throat. The instructor was impressed with Tholme's abilities as he hadn't noticed the Jedi before. When asked why he had returned to Anzat after so long and whether his hunt for Katichak had ended successfully, Tholme explained his search for Bulq and confirmed the assassin's death.
Since the Anzati Code of Honor stipulated that existing contracts should not be exchanged with outsiders, Seii refused to provide information to his former student, referring to his silence. He considered the conversation over because, despite his powers, Tholme would not be able to force him to speak about Bulq's visits to Anzat and he adhered to the Anzati Code. There upon, Seii and Tholme were attacked by his adepts. He had the intention of pointing out the lack of trainers to Anzat due to their unusually large number. He advised the Jedi that they would try to kill him and that he should therefore not be afraid to use lethal violence himself. Tholme managed to put all of the attackers out of action without killing any of them. Seii then ordered his students to go back to their studies. Tholme had recognized from the fighting style of the adepts that their training was not yet well advanced, and was amazed that Seii was training several students at the same time. The Anzati then indicated that there were no other teachers available on Anzat at that time. Tholme concluded that Bulq had recruited the Anzati for his purposes. The Jedi thanked Seii and then returned to his spaceship. Shortly afterwards he discovered the Morgukai shadow army on Saleucami, which was destroyed after a five-month siege by the Republic.
- Star Wars: Republic: Trackdown (First appearance)