Mortis was a planet enclosed in a monolith located in the remote Chrelythiumn system that was a conduit for the entire Force of the universe. Mortis became home to the Ones, a family of powerful Force users, years prior to the Clone Wars. Time was experienced differently inside the Mortis monolith than in the rest of the galaxy—standard days experienced on Mortis by Obi-Wan Kenobi, Anakin Skywalker, and Ahsoka Tano were only "a moment" experienced in normal space by Captain Rex.
- "Are we in danger?"
"This planet is both an amplifier and a magnet. Three are here who seek Skywalker. They, like me, believe him to be the Chosen One."
- ―Obi-Wan Kenobi and the spirit of Qui-Gon Jinn
Approximately 24,500 BBY, the Darksider Xendor journeyed to Mortis and met the Ones. However, he believed their claims on the nature of the Force had no more or less legitimacy than the teachings of any other Force group.
Sometime before 32 BBY, Darth Plagueis heard tales of the Jedi about Mortis and the three powerful beings who lived there. He wrote about Mortis while studying the Prophecy of the Chosen One in his science journal prior to his murder by his apprentice, Darth Sidious.
In 20 BBY,[source?] during the Clone Wars, the aging Father drew Jedi Knight Anakin Skywalker to Mortis so that the Chosen One could replace him as the keeper of the peace between his rival children, the Son and Daughter, who represented the dark and light sides of the Force, respectively. Skywalker arrived on Mortis with Jedi Master Obi-Wan Kenobi and Padawan Ahsoka Tano, but the Son separated the three Jedi by taking Tano hostage and forcibly turned her to the dark side in an attempt to turn Skywalker to the dark side of the Force.
The Daughter ended up sacrificing herself to save The Father from The Son's attack, and also spent the last of her energy to revive Tano via the Chosen One. The Son later succeeded in turning Skywalker to the dark side by exposing him to the actions of his future self, although The Father later eliminated his memories of the event after discovering this to break the dark side's hold on him. The Father later sacrificed himself by stabbing himself with the Mortis Dagger to weaken The Son enough for Skywalker to finish him off. After the Father's body vanished, the Force energies that permeated and sustained Mortis dissipated causing floating rocks to fall and even the crystal hovering above the Father's monastery fell and shattered. The planet was engulfed in a large explosion and returned Skywalker, Kenobi, and Tano back to realspace with the Monolith having vanished.
In 44 ABY, a group of Jedi Knights were dispatched by Jedi Grand Master Luke Skywalker, Anakin Skywalker's son, to search for the Mortis monolith. Their aim was to locate the Mortis Dagger, so that should Abeloth, the Force entity (and embodiment of the universal dark Mother) that had threatened to bring the galaxy to its knees, return in the future, the Jedi would be equipped to defeat her.
- Star Wars: The Clone Wars – "Overlords" (First appearance)
- Star Wars: The Clone Wars – "Altar of Mortis"
- Star Wars: The Clone Wars – "Ghosts of Mortis"
- Star Wars: The Clone Wars – "Voices" (Mentioned only)
- Fate of the Jedi: Apocalypse (Mentioned only)
- Crucible (Mentioned only)
- "Launch Pad"—Star Wars Insider 123 (First mentioned)
- "Secrets of the Force"—Star Wars Insider 123
- "Matt Lanter & the Rigors of Mortis!"—Star Wars Insider 123
- "Coming of Age"—Star Wars Insider 123
- Star Wars: The Clone Wars Magazine 3
- Star Wars: The Clone Wars Comic UK 6.17
- (Picture only)
- "50 Great Reasons to Rewatch Star Wars: The Clone Wars Season Three"—Star Wars Insider 125
- The Clone Wars: Secrets of the Force
- "The Write Stuff!"—Star Wars Insider 126
- Star Wars: The Clone Wars Comic UK 6.24
- Star Wars: The Clone Wars The Complete Season Three
- Book of Sith: Secrets from the Dark Side
- "Apocalypse... Now!"—Star Wars Insider 132
- "Back from the Depths!"—Star Wars Insider 132
- The Essential Guide to Warfare
- Star Wars: The Ultimate Visual Guide: Updated and Expanded
- The Essential Reader's Companion
- "Classic Moment"—Star Wars Insider 141