Zeffo, situated within the Outer Rim Territories, was a planet swept by electromagnetic wind. Abundant in water, its landscape was characterized by rugged mountains and steep cliffs, with grass covering much of its surface. The planet was dotted with ancient ruins and crypts, guarded by the Tomb Guardians. Various creatures called Zeffo home, including the Phillak and Scazz.
Once, Zeffo was inhabited by a community of archaeologists and pioneers who arrived during the time of the Galactic Republic. However, with the rise of the Galactic Empire, this peaceful community was decimated. The Emperor Palpatine sought valuable information on Zeffo, leading to the plundering of historical sites and sacred tombs.
Zeffo existed within the isolated Zeffo system, which itself was located in the Outer Rim Territories near the Veragi Trade Route. Specifically, it was found in the New Territories, the galaxy's northernmost region, within grid square M-3 of the Standard Galactic Grid. From a vantage point in space, it appeared as a green-blue sphere, partially obscured by large white clouds. This planet, rich in water and subjected to constant electromagnetic wind, also featured rocky mountains and cliffs covered in grass and snow. Dangerous fauna, such as the Jotaz, Phillaks, and Scazz, inhabited its lands. It served as the original homeworld for the ancient Zeffonians, and later, a small community of archaeologists and pioneers from the Galactic Republic settled there. Scattered across the landscape were numerous ruins, ancient catacombs, and tombs constructed by the Zeffonians, who were believed to have vanished by the Clone Wars. By 14 BBY, the Galactic Empire had occupied the world, leaving it slightly scarred due to the initiation of Project Auger.
In ancient times, Zeffo was the originating planet for the Force-sensitive Zeffonians. During their reign, they erected numerous statues and created various relics. They left behind many tombs dedicated to several Zeffo Sages, which were protected by Tomb Guardians.
During this period, archaeologists frequently visited the planet, hoping to uncover ancient Zeffo artifacts. Jedi Master Eno Cordova himself researched the tombs located there.
Sometime during this era, a Republic Venator-class Star Destroyer, commanded by General Chiata, crash-landed on Zeffo. Shortly after the crash, Chiata's unit of clone troopers executed Order 66, resulting in the deaths of Chiata and her Padawan, Marseph.
Under the Empire's control, Zeffo's ice caves and other areas were excavated as part of Project Auger. The Empire, in its search for Zeffo artifacts, displaced many Zeffo inhabitants from their villages, utilizing Imperial Code 94364.
Cal Kestis visited Zeffo on two separate occasions during this era, seeking out the Zeffo tombs that Eno Cordova had previously studied.
Later villagers on Zeffo held a strong reverence for the deceased, understanding that their sacrifices allowed the survival of the living. To honor the dead, they constructed stone sculptures that seemed to draw inspiration from ancient Zeffo architecture. The villagers also respected the clone troopers, erecting a memorial without knowing the truth of Order 66.
Zeffo was specifically designed as a planet for the video game Star Wars Jedi: Fallen Order, which was developed by Respawn Entertainment. Its existence was initially revealed through an entry on the Databank section of StarWars.com. The visual representation of Zeffo seen when the player journeys to the planet was the creation of George Rushing, a senior concept artist at Respawn.