The Kraaxaa-Tseetsk were twice the size of their Sree-Tseetsk cousins, approaching the size of a normal human. Their bodies were much leaner, with longer, stronger legs and longer arm-wings. In addition, the shape of their heads was altogether different, coming to a predatory-looking point in the front. Their beaks were large and curving. And their black eyes were smaller and set so far apart that one would doubt their vision was stereoscopic.
Ten thousand years ago the Kraaxaa-Tseetsk clan allied themselves with the Loor-Tseetsk clan and together they fought a war against the Sree-Tseetsk and Joost-Tseetsk clans. The Sree-Tseetsk eventually won the war, after they directed an asteroid on Koorn. It was initially believed that the three Tseetsk clans were wiped out.
However the Kraaxaa-Tseetsk clan managed to survive, living in the frozen wasteland of Koorn beneath the Rift. They managed to salvage remnant technology to use a geothermal tap to create a thriving colony beneath the ice.
By the 2360s decade of the 24th century, the Kraaxaa-Tseetsk were faced with encroachment by the Human slaves under the command of the Sree-Tseetsk. Many Kraaxaa-Tseetsk were killed by the humans' disruptors, devices which the avian race knew nothing about and attributed to the humans raised hands as death. The Kraaxaa-Tseetsk existence was reported to the Sree-Tseetsk regent, however lack of evidence lead to the regent ignoring these mythical creatures and attributed them as hallucinations by the humans.
Their existence was officially confirmed after Federation Starfleet officers Captain Jean-Luc Picard and Counselor Deanna Troi of the starship USS Enterprise-D along with Human slave Chu Edorlic were captured. The trio were brought before the Kraaxaa-Tseetsk and stood on trial for the humans crimes against their kind. Using the Kraaxaa-Tseetsk computer cube and Chu's limited knowledge of Sree-Tseetsk language, the three were able to convince the Kraaxaa that the humans on Koorn were victims just as the Kraaxaa and explained that the human slaves had revolted against the Sree. Taking this into consideration, the Kraaxaa agreed to postpone their executions, however they required the humans to assist them. It was learned that the Kraaxaa's geothermal tap was in a critical state of disrepair and that the Tseetsk needed new parts to repair it. They forced Picard and Chu to guide them to the abandoned slave camps where they could retrieve parts. On the way the pair of humans, suspecting that their avian captors would eliminate them after they served their purpose, managed to get the drop on their guards and escape into a downed overseer shuttle. While the shuttle prevented the Kraaxaa-Tseetsk from entering, the two managed to re-establish communications, notifying Enterprise of their location. Commander William T. Riker immediately sent aid to retrieve the captain and Chu and abduct Kraax-koorn-aka. The existence of the lost Tseetsk clan was notified to the Sree-Tseetsk ships who halted their retaliation attack on the Enterprise.
The Kraaxaa-Tseetsk were a patriarchal society. They held valor in battle as a sign of respect and scars were markers to prove their bravery. While the Kraaxaa had lost much of their technological knowledge they still retained a computer cube, maintained by a priesthood that held their recorded history. They were well aware of how their ancestors came to Koorn and held the Sree-Tseetsk in contempt.