Ashraks were highly skilled warriors that were able to survive for long periods of time in enemy territory. They typically wear an ornate form of armor with a special helmet that covers their eyes which has a visor for them to see their environment. However, when infiltrating another society, an Ashrak discards their armor and clothing in order to appear as a member of the infiltrated culture.
The healing abilities of a Goa'uld Symbiote are fully exploited by the Ashrak, who are capable of mending even the most grievous of injuries. In addition to this, they make use of specialist equipment such as the Hara'kesh which they are also capable of stashing in their mouths to be regurgitated when needed. This allowed an Ashrak to hide their equipment making it easier for them to infiltrate a society.
Some Ashraks were also equipped with cloaking technology, allowing them to stalk their enemies and cause a great deal of damage to even a large assembled force. When using cloaking technology the Ashraks usually are armed with A'tar Blade.
The Ashrak were feared by both Goa'uld and Tok'ra as they were dispatched to silently kill the enemies of the System Lords. This made them a form of enforcer within the Goa'uld Empire. (SG1: "In the Line of Duty", "Allegiance")
The Ashrak were created by the Goa'uld Selket who created an army of deadly elite assassins who would do her will. She handles the training of the Ashrak who are then contracted out to the System Lords for assassination duties. This would either be done on a single basis, in order for the contracting Goa'uld to remain anonymous, by contract or by permanently buying the services of the Ashrak.
They are trained in the technique (pioneered by Selket herself) of suppressing the identity of the host, which allows them to easily switch host bodies. They also faced intense brainwashing and indoctrination techniques that made them loyal to Selket. This, along with the fear of being hunted down by Selket, prevented them from betraying their mentor. (RPG: "First Steps: The Stargate Unexplored Worlds Roleplaying Sourcebook")
Among the stories of the Jaffa, there exists a true story of an Ashrak that infiltrated Apophis' mines on the planet Kawawn. After numerous killings, Apophis ordered the mine sealed off in order to flush out the killer. Several days later when the mine was reopened, only one Ashrak was found; a single one was responsible for so many deaths. (SG1: "Allegiance")
The System Lord Cronus dispatched the Ashrak assassin Edrekh to kill the Tok'ra Jolinar of Malkshur. Edrekh tracked the Tok'ra to the planet Nasya and followed her to Earth where the Tok'ra had since taken residence in the body of Major Samantha Carter. The Ashrak succeeded in its task but was killed when trying to escape thanks to Teal'c firing two shots from a zat which incapacitated the Ashrak before the second finally killed it. (SG1: "In the Line of Duty", "Fair Game")
Another Ashrak was deployed by Anubis with the task of fracturing the alliance between the Jaffa Rebellion, the Tok'ra and the Tau'ri. This assassin made use of cloaking technology and nearly succeeded in destroying the alliance as well as escaping in order to inform his master of his enemies' new base but was killed by Bra'tac. He also infiltrated the Tok'ra base in the Risa system and alerted Anubis of where to target so that he was able to easily bypass its defenses and destroy the base. This Ashrak's efforts backfired and instead of destroying the alliance, it brought the three groups closer together than ever. (SG1: "Allegiance")