Over twenty thousand years ago, the alien Rakata turned the jungle planet Belsavis into a prison. There, they entombed indescribable monsters, heretics and warlords, weapons to shatter stars, whole species… anything they feared or treasured above all reason. And when the Rakata's age of glory ended, the droids they left behind maintained the seals.
Many millennia later, after the rise of the Republic, Belsavis became known as an unremarkable planet in the middle of an ice age, populated by only a handful of primitives. It was only happenstance that caused Republic scouts to notice first the tropical rifts that defied the freezing temperatures, and then the strange vaults and the alien structures burrowing into the core of the planet.
Top-secret expeditions attempted to explore the alien vaults, until the extent of the dangers became apparent. At last, select Senators worked with the Strategic Information Service to construct Belsavis prison‒a facility with two purposes. First, to guard, contain and study the terrible alien structures on the planet. And second, to create a prison for the Republic‒one where the most powerful offenders could be placed within the Rakata's cells, and where lesser threats could be isolated on the most secure planet in the galaxy.