Physically, they had streamlined bodies with a pronounced keelbone mid-chest, batlike wings, a saurian tail, a long sharp beak and a shark-fin rudder on top of their heads. Their silver-scaled skin shimmered under light, with their scales' featherlike microserrations giving the refracting effect, making them look like rainbow-colored pterodactyls. At least one individual was shown to be over two meters tall. Their arms branched off at the elbow into two forearms each, giving them four hands with three talons each. The Shesshran required an atmospheric pressure 3.4 times, and gravity force 1.65 times that of a standard Class M environment. When in a Class M environment, they had to wear an air tank with a mask in order to breathe, and the gravity of such environments made their movements awkward, so they generally considered Class M worlds uninhabitable.
The Shesshran were an aggressive and highly individualistic species.
Circa 8000 BC, the Shesshran were known as the Tishiki. Because they had no use for a planet with a standard Class M environment like that found on Daran IV, the Tishiki offered the planet to the Fabrini when they learned that the Fabrini star would soon go supernova.
When the Fabrini star did explode, the death of the star had a serious negative effect on Kachissat, killing many of the Tishiki. Those that survived lost much of their technology in the chaos, which would later become known as the Great Die-Off. Over the next ten millennia, the survivors became known as the Shesshran, and evolved into a race of avian raptors.
The Shesshran made first contact with the United Federation of Planets in 2264 when the Vulcan-crewed USS Intrepid entered the system to conduct a survey of the system. The Intrepid was detected by the Shesshran, who launched an attack on the starship despite its superior technology. They subsequently entered into a dialog with the Vulcans, but asked them to leave the system when the Vulcans refused to share technology with them.
When the Fabrini ship Yonada appeared in the Daran system, and was found to be on a collision course with Kachissat, the Shesshran prepared to attack the world ship. However, the USS Enterprise was able to put Yonada back on course for Daran IV. The Shesshran were at first reluctant to share their star system with the Fabrini, but later consented to allow them to settle Daran IV when archaeological evidence was uncovered proving their ancestors had indeed promised Daran IV to the Fabrini. (TOS novel: Ex Machina)