Zeferi was a highly Force-sensitive Zartan with a gift for prophecy. She foresaw the destruction of her homeworld by the Empire when she was eight years old, but not even her parents listened to her. When Zarta finally was destroyed, her parents died in the ensuing carnage, and she was adopted by a Talz named Smuh. He raised her as his own daughter until her power in the Force came to the attention of Master Luke Skywalker in 11 ABY, at which point she was brought to the Jedi Academy to study under him. She was one of the apprentices who combined powers with Dorsk 81 to defeat the Imperial Fleet, and later went on to attain the rank of Knight. Her gift for prophecy grew stronger, and she eventually began to refer to a Chosen One who would bring balance to the Force. This prophecy was eerily similar to the one about Anakin Skywalker, which worried many members of the New Jedi Order who did not want to see another Sith Lord. During the Phyrexian War, Zeferi accompanied several other Jedi Masters to the Valley of the Jedi. It was during the early stages of this campaign that she discovered she could sense the Yuuzhan Vong High Priest, Harrar, in the Force. She realized that he was the Chosen One whose coming she had foretold, and that the balance he would bring to the Force involved the Forceless Yuuzhan Vong somehow. She got permission to train him as a Jedi, and he accompanied her as an apprentice during the mission to the Valley of the Jedi. Harrar was killed in the Battle of the Valley, but his sacrifice allowed other Yuuzhan Vong to exist within the Force where they could not before, thus fulfilling Zeferi's prophecy.
By the time of the Sith Crusade, Zeferi had a seat on the Jedi Council. She survived the Battle of Ossus, and went on to defy Presidential Order 0139/D. It is unknown what became of her afterward, but sometime following the battle of Coruscant she assumed the title of Grand Jedi Master. Following her death, she was succeded as Grand Jedi Master by Tai painj.
Zeferi's lightsaber was blue, and seems to have been a fairly standard model.