The Molt Swimmer was the first creation ever devised by the Darksider known as Sivter. It was a testbed for him to experiment and familiarize himself with Sith alchemy. As his template, Sivter used the most advanced creature on Arcanix to create the molt swimmer: a small simple celled organism, which he dubbed “lava swimmers,” that actually lived within the lava flows of the planet - feeding on the volcanic minerals. Their ability to survive in such extreme heats would see Sivter use them for several other creations down the road.
Through successive lava swimmer generations, Sivter would graft the DNA of other animals onto them until eventually he was satisfied that he understood the true power and limitations of Sith alchemy. The final result would eventually become known as the molt swimmer, which had a double meaning to the name. It referred to their ability to swim in molten lava like their smaller predecessors and their ability to use the cooled lava on their body as armor before molting it when it became unusable.
Since they derive from such simple organisms, molt swimmers grow quickly and reproduce asexually. When Sivter released his experiment out into the barren wilds of the planet, the molt swimmer numbers rapidly increased to such a degree that it forced Sivter to create the Arc Ghoul to keep them under control.
Even though molt swimmers are one of the few creatures on Arcanix that don’t hunt other animals or people, they can still be fearsome in a fight. Aside from the considerable size and strength of a fully-grown adult, the molt swimmer can spew the molten materials it keeps stored in its body at its attackers. Blasters have little effect on molt swimmers since they regularly endure much greater extremes in the lava, and their hardened lava coating helps to protect them against melee weapons. Lightsabers are effective, but the insides of molt swimmers are on par with that of active volcanoes and can fry unwary Forcers who get too close.
Molt swimmers are completely blind; on the dark planet of Arcanix eyes are of little help, and even less so when swimming through lava. To compensate, they possess superior hearing, listening for underground lava flows and then using their diamond hard claws to rip apart the ground and feed on the lava. They are solitary animals, roaming the planet and feeding on the lava. Their young are birthed in the lava to help protect them from predators, but that is the extent in which the molt swimmers look after their offspring.