Cuthallox was the Padawan of Jedi Knight Blendri serving the Jedi Order on Ossus during the Order's early years. Joining her master and several other Jedi, Cuthallox became a Jedi Renunciate and a Legionnaire of Lettow, one of the many followers of Xendor during the First Great Schism.
A Force-sensitive, Cuthallox lived on Ossus, the home of the Jedi Order during its early years. Apprenticed to the Jedi Knight Blendri, Cuthallox and Blendri became enamored with the enigmatic teachings of Xendor, who preached that the Jedi High Council was too restrictive in their teachings and wished to limit understanding of the Force. When Xendor parted with the Order to found an academy on Lettow, Cuthallox and Blendri departed with Jedi Master Jook-jook H'broozin to learn from Xendor. Calling themselves the Legions of Lettow, the Jedi Renunciates grew strong in the Force as they studied the Bogan through many different Force-traditions.
When the High Council declared war on the Legions of Lettow, Cuthallox and Blendri took up swords to protect their right to study the Force. Meeting the Order in a full-blown conflict called the Great Schism by the Order, the Master-Padawan pair jumped from world to world to fight off the Jedi. At the battle of Corulag Jedi Padawan Danzigorro Potts killed Master H'broozin and attempted to kill Cuthallox and Blendri but the pair managed to escape. Padawan Potts would continue to hunt the pair throughout the war until he finally met them on the field of battle at Columus. Engaging Potts, Cuthallox was outmatched and killed.