Kabis Borreto is a civilian, captaining a privately-owned cargo hauler named Leo Fortune. He considers himself moral and upstanding, but is also well-accustomed to sourcing paying passengers and cargo consignments from the notoriously criminal Backwaters.
At some point in 3745 ELC, Kabis Borreto encountered the fugitive Maber Castigon and a deal was struck between them. In need of revenue to help his pilot and engineer get the ship back up to scratch, Borreto agreed to take Castigon to a number of Imperial Combine worlds for short stops. He did not ask what the nature of Castigon's business would be on those planets (→LOTD).
Arriving at the remote colony world of Lophrit to find the towns there devastated, Borreto began to form suspicions about Castigon. He was right, albeit for the wrong reasons, and in his own typical fashion he was not shy about voicing his concerns. There was a verbal confrontation between the two men over discretion, during which Borreto got a sense of the threat Castigon posed. Substantially more money was then negotiated for the fugitive's carriage aboard ship (→LOTD).
Conversation between Borreto and engineer Prayer Monsul during that same incident on Lophrit suggested that both of them had previously been involved in disaster recovery operations in which there was a high fatality rate (→LOTD).
Borreto also took Castigon to Serrofus Major, despite warnings from the captain that civil unrest was brewing there. Borreto showed greater discretion on Castigon's return — not even commenting on his new facial injuries — and then took him on to Altakanti Station, an Imperial Combine listening post. The risks involved in navigating the asteroid field in which Altakanti was located, and in being in such close proximity to a military base, were not lost on Borreto. Because of these risks he again felt that he deserved more information and he queried Castigon's intentions. From the reaction he got, he determined that Castigon was ex-military and that the dangers associated with him might not be worth the money involved (→LOTD).
While Castigon was aboard Altakanti Station, Borreto discussed his concerns with Prayer Monsul and pilot Sayad Idiri. Borreto wanted Castigon off the ship, but was adamant that he could not be simply left behind. To his credit Borreto even risked damage to the ship and harm to his crew in order to recover Castigon from Altakanti (→LOTD).
Later, in distant orbit of Meccrace Prime, Borreto became complicit in Castigon's deceptions by obtaining a transponder code that would allow the fugitive to triangulate Elm Caden's approximate location on the planet (→LOTD).
Castigon failed to return from the surface, but prior to leaving orbit the Leo Fortune was witness to the invasion of the entire planetary system by Shaeld Hrathan dreadships. Realising that this same threat must have been responsible for Lophrit, it was Borreto who sent a databurst containing footage of the attack to the entire public network of the Imperial Combine (→TRD).
The government was not impressed with the footage being released, and the crew of the Leo spent some significant time hiding from patrols. It was during this period that Sayad Idiri informed Borreto of the strange behaviour of the ship's wormholes. They did not know it at the time, but Borreto's ship was experiencing the same navigational issue which had also begun to affect all Imperial Navy vessels. Unable to solve the problem themselves, Borreto agreed that the only viable solution was to head for an Imperial Combine facility capable of performing a deep diagnostic, where the three would doubtless have to hand themselves in as the senders of classified information (→TRD).
Arriving at Fort Herses with the intention of throwing himself on Imperial Combine mercy, Kabis Borreto was intercepted on the docking ring by March Bel-Askis who was — at the time — fleeing assassination. The senior member of Eyes and Ears transferred so much money to Borreto that the captain threw caution to the wind, electing to cast off immediately without having any diagnostic work performed on the Leo (→TRD).
The current whereabouts of Borreto and the Leo Fortune are unknown.