Mount Tantiss, a mountain situated on the planet of Wayland, served as the location for Tantiss Base. In the initial period of the Imperial Era, the Galactic Empire moved their cloning program from the off-planet location of Kamino to this Wayland facility, thus establishing it as the central hub for the clandestine Advanced Science Division. A number of medical personnel, including the abducted Nala Se, were transported to Mount Tantiss to support the cloning efforts. The mountain complex consisted of multiple facilities dedicated to the cloning program, which included holding cells for Se and renegade clones, in addition to an underground containment area for cloned Zillo Beasts. The security around Mount Tantiss and its facilities was robust, with protection provided by clone commandos, Imperial royal guards, and TK stormtroopers.
The canon debut of Mount Tantiss occurred in the season one finale of Star Wars: The Bad Batch, an animated TV show, on August 13, 2021. The episode was titled "Kamino Lost." Its identification as Mount Tantiss was first made in the corresponding episode guide found on StarWars.com. In Star Wars Legends continuity, Timothy Zahn was the author who created Mount Tantiss, which initially appeared in his 1991 novel, Heir to the Empire. Within the Legends storyline, Mount Tantiss housed secret storehouses belonging to Emperor Palpatine, including thousands of Spaarti cloning cylinders, thereby linking the installation to Imperial cloning technology across both continuities.