Ilon Tandro was a Klaestron, the son of General Ardelon Tandro and Enina Tandro.
Although he was too young to have any real recollection of his father, Ilon grew up venerating his father's memory, and was determined to find his murderer, in spite of his mother's efforts to deter him.
In 2369, he visited Deep Space 9 and attempted to kidnap Jadzia Dax. When caught, he revealed that he was the special envoy sent to extradite her under Klaestron law, for the murder of his father. Determined to protect Dax, Commander Benjamin Sisko suspected that Tandro's kidnapping was to avoid any involvement with the Bajorans, as Deep Space 9 was technically in their territory, and Major Kira Nerys declared that on behalf of Bajor that for circumventing the station's security, they had grounds to deny extradition.
Ilon was forced to make his case before Arbiter Els Renora that Curzon Dax betrayed his father to rebel forces during the Klaestron Civil War; old military records had been recently disclosed which suggested that Curzon Dax had been responsible for sending the transmission that resulted in Tandro being caught, as Curzon was one of the few people who knew where Ardelon would have been when he was killed and was the only one of those few whose location at the time of the transmission was unaccounted for. He believed the Dax symbiont to be responsible for his actions and was attempting to evade the consequences by transferring to another host. Sisko argued that the person Tandro wished to extradite no longer existed and challenged him to prove otherwise. The resulting extradition hearing became a contentious contest between the two men over whether Curzon and Jadzia were the same person who allegedly committed the crime.
As Jadzia was forced to take the stand, Tandro began to question her aggressively if Trill symbionts should be responsible for past crimes. However, the hearing was interrupted by the surprise arrival of Enina Tandro, who admitted that at the time her late husband was ambushed, she and Curzon had been in bed together and thus couldn't have betrayed Ardelon to the rebels. With his case against Jadzia disproved, Els formally denied extradition. A stunned Ilon also recoiled from his mother's touch while trying to reconcile her infidelity.
In truth, it was in fact Ilon's father who sent the transmission, having planned to defect to the rebels only to be killed instead. Curzon had sworn himself to secrecy to protect Ardelon's reputation. (DS9: "Dax")