The Okaati fleet is a migrant fleet whose excursion through the cosmos began during the sixth-millennium, after departing their native homeworld following an ecological holocaust of their own making. They are encountered by the Fleet in the seventh-millenium after entering the Empyrean Expanse.
Initially pacifistic and humble, the Okaati became parasitic in their wayward exile due to resource scarcity and other socio-political factors, with adeptness at stripping resources from the worlds within the Empyrean Expanse using their Harvesters. These Harvesters demonstrate the Okaati's engineering acumen, for their speed and scanning ability allow them to quickly strip ships and planets for resources, as they became increasing aggressive and create an enemy of their own making: the Comitat, an assemblage of victimized species seeking both justice and containment of the Okaati (Battlestar Galactica Classic #4). The Okaati do not have fighter craft of their own, thus finding themselves at the mercy of Bladeships and heavily reliant on their speed (Battlestar Galactica Classic #0).
In the intervening millennia, the Okaati became a scourge that outpace and outwit the Comitat, striving to find sources outside of the Expanse. This search, lead by their leader Parrin sometime in or about 7349, results in contact with the Cylon Empire's emissaries Baltar and Lucifer. Upon their return into the Expanse, Parrin and her Cylon escort are detected by Blue Squadron following its fracas with the Kiernu. Believing the Raider escort to be attackers to the then-unidentified vessel, Captain Apollo and fellow Warriors dispatch the escort, handle an enemy with presumed similarities to the Cylons, and are introduced to this fugitive fleet numbering at least 220 ships (Battlestar Galactica Classic #0, #1 & #3).
Turning Point with Humanity
After dispatching the Cylon Raiders and the Comitat's bladeships, Captain Apollo's squadron is led to the Okaati fleet and lead to believe that the Okaati share the same perilous journey through the cosmos as a "fugitive fleet." Buoyed by the possibilities of an alliance with fellow victims of oppression, Apollo leads the Okaati to the human's Fleet (Battlestar Galactica Classic #0).
Believing that Parrin's plan to use the Fleet in order to barter for tylium from the Cylons would work, the Okaati engineers engage in deception to hijack the Fleet's various ships (sans Galactica) by conjoining each Fleet vessel with a Okaati Harvester, allowing the Harvester to disable and stage its Colonial partner on Gehenna Prime to this end (Battlestar Galactica Classic #3—#5).
Following the Battle at Gehenna Prime, the Okaati's fleet is disbanded and the Okaati are resettled on the former Kiernu homeworld (Battlestar Galactica Classic #5).