In the ancient past, the Sith Lords of Korriban perfected an art they called alchemy‒a synthesis of scientific lore and dark side philosophy. Sith alchemy was a tool to transform life itself, to reshape flesh and bone and create terrifying servants out of mere animals.
Creations of Sith alchemy are called Sithspawn. Each is unique, crafted by the hand of a Dark Lord with monstrous intent. Most are ancient, as few Sith continue to practice alchemy; although the art is not lost, it has fallen out of favor. A Sithspawn is unnatural by definition, built for near-immortality and typically violent beyond measure; a perfect weapon, and if bound, a perfect guardian.