Kal-Don was a famous Jedi Master stationed at the Jedi Temple on Coruscant. During his tenure as Jedi Master, Kal-Don accepted the infamous Cerean, Ter-Idi as his Padawan. Running through Ter-Idi was an apathetic streak towards the lure of the dark side, something that concerned Kal-Don and the other Jedi Masters. Their worst fears were realized when Ter-Idi suffered an incapacitating injury at the hands of an assassin attempting to murder Master Kal-Don.
Through his recovery, Ter-Idi realized that the injury would leave him less agile than before. As frustration set in, the lure of the dark side offered to replenish his speed and strength to levels greater than before the trauma. Unfortunately, Ter-Idi`s apparent indifference to the dark side made his fall that much easier. Ter-Idi left Master Kal-Don and the Jedi Order, never to be seen again by Master Kal-Don or any other Jedi.