The Sith Assassins are a sect of covert Force-sensitive killers secretly founded by Darth Revan on Malachor V during the Mandalorian Wars. Captured Jedi and Sith soldiers who were found to be Force-sensitive were taken to the Trayus Academy to be trained as Sith assassins. These assassins were largely responsible for carrying out the First Jedi Purge that began in 3954 BBY until their defeat and disbandment in 3951 BBY following the Destruction of Malachor V.
Later, the term is used for Sith Inquisitors who fought for the returned Sith Empire during the Great Galactic War and the Cold War that followed it circa 3653 BBY. These Sith assassins specialized in stealth and dealing high amounts of damage to enemies in melee combat. They are known to primarily wield saberstaffs in combat, and were adept at concealing themselves with the Force.