Kaagh

Commander Kaagh the Slayer was attached to the Tenth Sontaran Battle Fleet's Special Assault Squad. He was the lone survivor of a failed invasion of Earth by the Sontarans.

Avenging his Race
When Luke Rattigan destroyed the Sontaran flagship (DW: The Poison Sky), Kaagh's space pod was sent off course and crashed down to the planet Earth. Despite damage to the ship and exposure to G-force which might have killed him, injured and scarred on his face and one hand, Kaagh survived. As part of the Special Assault Squad, Kaagh's purpose was to infiltrate deep behind enemy lines in order to predict and anticipate their movements.

Kaagh hoped that by doing this he could make up for his fleets failure to conquer Earth. He began to began a covert attempt at destroying Earth and make 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, which 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. However Sarah Jane suspected that he would one day return. (SJA: The Last Sontaran)

Return of Kaagh
A few weeks after this he met Mrs Wormwood, a member of the Bane Family they had been angry at her and he aided her so that they could survive. They both plotted to become Emperors of the Galaxy and had defended her when he shot a member of the Bane Family. (SJA: Enemy of the Bane) He wanted to return back to Sontar, but was unable to as he couldn't take the shame of being defeated by "a female primitive and half-forms." In the end, he saved the universe from destruction by pulling Mrs Wormwood and himself into the portal to where Horath's consciousness was, which was in fact a black hole.

Equipment
Kaagh had access to an even higher level of technology than the likes of Commander Skorr. He had a smaller, more compact blaster weapon, a different type of communicator, an automatic helmet that could retract into his armour and a personal cloaking field. He also employed the use of neural implants as opposed to the more common hypnosis methods Sontarans tend to use. Kaagh sent out drones that resembled large plasmic spheres to act as scouts but also had attacking ability. (SJA: The Last Sontaran). His communicator also seems it can power other electronic weapons such as Mrs Wormwood Sonic disruptor. (SJA: Enemy of the Bane)