Planet of Origin:
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 more aggressive species, and their home planet was destroyed too. They travel for 1400 years until their arrival in our galaxy, where they attempt to rebuild their empire at the expense of others.
Apart from this, extremely little is known about the Saer'nar. 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")