In 19 BBY, a skirmish took place on the planet Zeffo between the clone troopers of the Galactic Empire and the Jedi Chiata and Marseph as a part of Order 66. Following a naval battle with heavy damage sustained, the unit formerly led by Chiata hunted and killed both Jedi.
In 19 BBY, a clone trooper unit led by Jedi Master Chiata fought in one of the final naval battles of the Clone Wars against a Separatist dreadnought. Due to heavy damage sustained to the unit's Venator-class Star Destroyer, they exited hyperspace above the Outer Rim Territories planet Zeffo and the ship crashed on the planet surface below. Having survived the crash, Chiata began a search for her Padawan Marseph. By this time, Supreme Chancellor Sheev Palpatine commanded the clone troopers of the Galactic Republic to execute Order 66 and kill all Jedi for treason against the Republic. Having received this communication, the remaining clone troopers initiated a hunt for the two Jedi under Palpatine's new Galactic Empire.
Marseph hid in the ship's vents as the troopers searched for him, and eventually he was found by Chiata. The two fought and killed most of the clones, but they were both fatally injured. A wounded Chiata kneeled from exhaustion and begged Marseph to run, and when she died, her Padawan buried her. Not long after, he too succumbed to his injuries.
Having no knowledge of what occured in the skirmish, the native Zeffo villagers constructed a memorial to the fallen troopers.
In 14 BBY, during a mission to Zeffo as part of his secret mission to rebuild the Jedi Order, surviving Jedi Padawan Cal Kestis visited the ship's Crash Site and used the Force power of Psychometry to discover the events of the skirmish.
The skirmish on Zeffo was mentioned in the 2019 video game Star Wars Jedi: Fallen Order, developed by Respawn Entertainment.