In the year 19 BBY, as part of the infamous Order 66, a minor battle, or skirmish, transpired on the planet of Zeffo. This conflict involved clone troopers serving the newly formed Galactic Empire against two Jedi, specifically Chiata and Marseph. The Jedi were hunted down by Chiata's former unit and killed, following a naval battle where the unit suffered substantial damage.
Back in 19 BBY, Jedi Master Chiata commanded a clone trooper unit during one of the Clone Wars' final naval engagements against a Separatist dreadnought. Their Venator-class Star Destroyer, the unit's vessel, was critically damaged, forcing them to exit hyperspace above Zeffo, a planet in the Outer Rim Territories. The ship then crashed onto the planet's surface. Chiata, surviving the crash, began seeking her Padawan, Marseph. Around this time, Supreme Chancellor Sheev Palpatine issued Order 66, commanding all clone troopers of the Galactic Republic to kill all Jedi, accusing them of treason. Upon receiving this directive, the remaining clone troopers of Palpatine's new Galactic Empire initiated their pursuit of the two Jedi.
As the troopers conducted their search, Marseph concealed himself within the ship's ventilation system. Ultimately, Chiata located him. The two engaged the clones, eliminating most of them, but both Jedi sustained mortal wounds. Exhausted and injured, Chiata knelt and urged Marseph to flee. Following her death, her Padawan buried her. He, too, succumbed to his injuries shortly thereafter.
The native Zeffo villagers, unaware of the actual events of the skirmish, erected a memorial to honor the fallen troopers.
Years later, in 14 BBY, Cal Kestis, a Jedi Padawan who had survived Order 66 and was on a secret mission to rebuild the Jedi Order, visited the Crash Site during a mission to Zeffo. Using the Force power of Psychometry, he was able to uncover the true events of the skirmish.
The conflict on Zeffo was referenced in the 2019 video game Star Wars Jedi: Fallen Order, which was developed by Respawn Entertainment.