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 apprenctice, 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 that had threatened to bring the galaxy to its knees, return in the future, the Jedi would be equipped to defeat her.