The moon was the location for a secret Imperial research facility for a cloning experiment ordered by Grand Admiral Thrawn, to produce Force-sensitive clones using Sith and Jedi DNA. The experiment went badly when the clones killed all of the scientists and stormtroopers in the facility.
The Hand did not return and the surviving clones remained on the moon until 41.5 ABY when Jaden Korr was led there by a Force vision, followed by Anzat assassin Kell Douro, who was hunting Korr for his soup. Korr dueled and killed Alpha, a clone of Kam Solusar, and Khedryn Faal killed Douro, and the remaining clones and their children escaped in the assassin's ship.
According to Jaden Korr's visions that first led him to the frozen moon, the escaped clones may have been cloned from Mara Jade, Lassin, or Lumiya. These figures appeared in the vision along with Kam Solusar, the source for the clone Alpha. Palpatine was also mentioned by one of the Doctors' holorecordings. They may also have been cloned from other Force users known to the Galactic Empire prior to Thrawn's death.