Styre

Styre was a Sontaran Field Major with the G3 Military Assessment Survey. He reported to an unnamed Marshal.

At some point he was ordered by the Grand Strategic Council to make an assessment of human physical limitations.
 * Apparently Styre's mission was of some urgence, as it was noted by his superior that "the entire invasion fleet" was held up by his delay. The Doctor claimed they were probably going to invade the entire Mutter's Spiral.

For this purpose, he lured 8 human soldiers from GalSec to an abandoned Earth in order to subject them to a number of experiments. Amongst the things he tested were their reaction to fear, muscular strength, and the resistance to pressure on the human breast case, using a gravity bar. Styre particularly noted that humans were highly dependent on fluids and if they did not drink they started to lose mental and motor skills in as little as 3 days, which he thought should be exploited.

He was defeated by the Doctor, Sarah Jane Smith, and Harry Sullivan. Styre died after connecting his probic vent to his ship, which Harry had earlier sabotaged, so rather than absorbing energy from the ship via his probic vent, the ship drained Styre's energy. (DW: The Sontaran Experiment)
 * As Sarah Jane noted, Styre appeared identical to Linx in most ways. However, unlike most Sontarans, Styre had five rather than three fingers on each hand. Sarah Jane's reference was to show that the Sontarans were cloned and that all are nearly identical.