Rako Hardeen had aspirations for greatness -- he wanted to stand shoulder-to-shoulder among the legendary bounty hunters of his era, hired guns like Cad Bane, Embo and Twazzi. A crack shot, he was reputed to be the best marksman from Concord Dawn, but he never gained the notoriety he desired. That is, until the day he killed Obi-Wan Kenobi...
Hardeen was hired by a mysterious client to target Kenobi. He succeeded, just barely outrunning Kenobi's vengeful former apprentice, Anakin Skywalker. Hiding out in the seamy depths of Coruscant, Rako was shocked to discover his client was the Jedi Council. it was part of a secret plot to replace Hardeen with a Jedi agent to infiltrate the criminal underworld.
Kenobi used a concealed blast vest to protect himself from what appeared to be Hardeen's killing blow. The Jedi Master plummeted from a rooftop to the grimy streets of Coruscant, and hid his life signs by ingesting a vitals suppressor. As far as the galaxy was concerned, Obi-Wan was dead.
Anakin Skywalker was enraged at the death of his former Master. He captured Hardeen in the Coruscant underworld, and would have slain him if not for realizing that Obi-Wan would have objected. Little did Anakin suspect that the fugitive he caught was in fact a disguised Obi-Wan,
To complete his disguise as Rako Hardeen, Obi-Wan Kenobi swallowed a vocal emulator, a device that analyzed Hardeen's voice print and modified Obi-Wan's larynx to provide a perfect duplicate.