The Saer'nar race is an asexual, nomadic species from the planet Ekufrolx'nsian in the Andromeda Galaxy, who once had a proud empire. They were driven out from their space by a un-named more aggressive species, and their home planet was destroyed too.
They leave to travel to the Milky Way around the year 1200 CE. They travel for 1400 years until their arrival in our galaxy ,in the year 2600. where they attempt to rebuild their empire at the expense of others. Although just a few years before in the 1190s CE there was a Saer-Nar cruiser sent ahead as a scout that ended up doing alot of destruction to the Federation in the year 2598.
Apart from this knowledge on where they came from and that the Saer-Nar Fleet is getting ready to arrive in the Milky Way galaxy, extremely little is known about the Saer'nar themselves. Ella Donares, an agent for Section 31, saw a very brief image of a Saer'nar, but she described it as so terrifying she didn't want to recall it.
When arriving in the Milky Way Galaxy, a single Saer'nar cruiser was sent ahead of the rest of its fleet. One of it's purposes was for scouting and reconnaissance, and the other was to attack a key Federation world. On the journey it crossed Klingon space, eliminating several ships. On arrival at it's target, it dissipated the planet's atmosphere, before being destroyed by Federation forces. (PIO: "On a Knife Edge")