Sunaj Aldrenn was the father and master of Sorani Tillin. Once a Jedi Master, he fell to the dark side and became Darth Fernus. As Darth Fernus, he trained Maraz Vax after incinerating Maraz's homeworld, Ninergo. After Maraz defeated him, Allahandria rescued him and brought him away from the dark side. He took back his original name and was a Gray Jedi for the remainder of his life. Both of his arms were mechanical, and were built and maintained by his ex-wife, Magia Aldrenn.