Ambaln was a male Mon Calamari Jedi Knight prior to the Clone Wars. A Jedi investigator, Ambaln fell to the dark side of the Force while undercover and fled to the Outer Rim Territories with plans to build his own dark version of the Jedi High Council.
Discovered to be Force-sensitives by doctors on Dac, Ambaln was turned over to the Jedi Order for training in the Jedi ways. Entering into the academy in the Coruscant Jedi Temple, Ambaln eventually graduated and was selected by a Jedi Master for training as a Padawan. After years of one-on-one training, Ambaln passed the Trials of Knighthood set forth by the Jedi High Council and was elevated to the rank of Jedi Knight.
As a Knight, Ambaln trained independently as a Jedi Sentinel, joining the Acquisition Division of the Order as a recruiter. Like many recruiters, Ambaln also was a skilled investigator, taking missions from the Council of First Knowledge and Jedi High Council to track down criminals and bring them to justice. On one such assignment, Ambaln spent eighteen months undercover in an attempt to infiltrate a large crime syndicate. While undercover, the Mon Calamari fell to the dark side of the Force, though he returned to the Temple when his mission was completed. The Council was unaware of his fall, and Ambaln was dispatched by the Acquisition Division to pick up a Force-sensitive girl on the Outer Rim planet Lobaoc.
Taking a Whitecloak fighter from the Temple's starfighter pool, Ambaln arrived on Lobaoc and convinced the girl's parents, marsh farmers by the surname of Glirin, to let him take her for training at the Temple. Jedi Ambaln did not intend to take the girl to Coruscant, however. Instead, he planned to take her as his own student and corrupt her to the dark side so that eventually he could create his own Jedi Order. Not long after. the High Council realized that Ambaln had lost his way and sent a Jedi team to capture or, if needed, kill the Dark Jedi.
Discovering his abandoned starfighter a mile outside of the village of Koab, the Jedi team discovered the girl alone inside. Retrieving the girl, the Jedi realized they were not alone but in fact a J9 worker drone designated Z-N0 was aboard. The droid, assigned to Ambaln by the High Council, led the team to the boathouse where Ambaln was supposedly waiting. However, as the Jedi crossed a causeway to the boathouse they were attacked by Force-controlled dianoga. While several Jedi were wounded in the attack and Z-N0 fell into the marsh, the remaining Jedi searched the boathouse, finding it abandoned. The Jedi deduced that the Mon Calamari had fled through the marsh, later finding that he had taken his starfighter off planet with the young girl still aboard. Offworld, Ambaln planned to return to Lobaoc with his new acolyte to begin her training in the dark side. Meanwhile, the Jedi team pursuing him recovered Z-N0 and planned on using the droid to help track the Dark Jedi and recover the girl he had kidnapped.