Between the years of 19 BBY and 14 BBY, Iskat Akaris, an Inquisitor, extinguished the life of a female Zeltron Jedi while the Jedi was on a mission to Firrhana.
At some unknown time, a Zeltron female became a member of the Jedi Order. Following the commencement of the Jedi Purge, she fled and arrived at Firrhana, only to be captured by the bounty hunter Jakadis and imprisoned within his stronghold. The former Jedi Knight Iskat Akaris located her there, and, preventing any opposition to the dark side, killed the Zeltron as she rose in elated surprise. This act, along with the deaths of two other Jedi on the planet, resulted in Akaris being designated the Thirteenth Sister.