The Special Assault Squad was a division within the Sontaran Empire.
It was charged with engaging in covert assaults and its soldiers were skilled in fighting behind enemy lines, making use of cloaking technology. Members of the Special Assault Squad were assigned to various Sontaran units, regiments and fleets, such as Commander Kaagh, who was assigned to the Tenth Sontaran Battle Fleet (TV: The Last Sontaran) and others like Commander Tarx and Commander Lohr. (PROSE: The Last Sontaran)
When flagship of the Tenth Sontaran Battle Fleet was destroyed, (TV: The Poison Sky) Commander Kaagh, a member of the Special Assault Squad, crashed in his Pod onto the planet Earth. Despite damage to the ship and exposure to G-force which might have killed him, Kaagh survived, suffering a large scar down the right side of his face.
Kaagh hoped that he could make up for his fleet's failure to conquer Earth. He began a covert attempt at destroying Earth and making himself a hero, "Kaagh the Avenger", then "Kaagh the Destroyer". To this end, he used a neural control implant on Professor Nicholas Skinner and his daughter Lucy, both of whom ran Tycho, a radio telescope nearby. Kaagh planned to use the telescope to bring down Earth's many orbital satellites in a coordinated attack on the planet's nuclear power plants. This would have rendered the planet uninhabitable.
His plan was discovered by Sarah Jane, her son Luke and their friends Clyde and Maria. Kaagh attempted to kill her and her young friends whom he considered as "half-forms". However before his plan could come to effect, Kaagh was attacked in his probic vent by Maria's mother, Chrissie, and forced to return home to Sontar in his scout-ship. (TV: The Last Sontaran)
Too ashamed to return to Sontar, Kaagh began working as a mercenary for the Bane, who had found the consciousness of Horath and used Kaagh as a go-between for its transportation from planet to planet. A few weeks after this he met Mrs Wormwood, a member of the Bane family whom had been cast out for her actions. He found that there was a high price on her head, but she persuaded him to help her control the universe. They both plotted to become Emperors of the Galaxy.
Mrs Wormwood travelled to Earth, closely followed by Kaagh, who came in during a siege by the Bane Kindred. He found Mrs Wormwood and killed her attackers. They then stole Luke and the Tunguska Scroll, which would show them where Horath was buried. Luke escaped, but Kaagh managed to catch him. However, Mrs Wormwood was growing tired of him. In the end, she offered Luke a place at her side and double-crossed Kaagh, calling him a blundering idiot. Eventually he saw the light and in a last ditch attempt at honour he threw himself and Mrs Wormwood into the portal to Horath's body. (TV: Enemy of the Bane)
Members of the Special Assault Squad had more advanced technology than normal Sontaran troops. They had smaller, more compact blaster weapons, which seemed to have different settings. They housed their guns in a pocket which was connected to a leg.
They had automatic helmets that could retract into their armour and a personal cloaking field. They employed the use of neural implants, as opposed to the more common hypnosis methods Sontarans tended to use. They also used drones that resembled large plasmic spheres to act as scouts, but also had attacking ability. (TV: The Last Sontaran)
Their communicators could be used to control their drones and Neural control implants. (TV: The Last Sontaran) These communicators could also power other electronic weapons such as sonic disruptors. (TV: Enemy of the Bane) They also were able to tell their Sontarans if there is someone on their ship. (TV: The Last Sontaran)