Snathe

Colonel Snathe was a Sontaran who served as a commanding officer in the Imperial Sontaran Fleet, before he was banished to the planet Serac for failing to secure the Betrothal of Sontar, a Sontaran mining ship which he commanded, along with the rest of its crew. He was forced to work with the pacifistic Commander Lerox whose kind he saw as mongrels. To restore his glory, Snathe began searching for the Thanatos, which was believed to be the most powerful superweapon ever created. Snathe had the Sigil of Thanatos tattooed onto his chest, to remind him of his search.

When the Tenth Doctor arrived with Rose Tyler, they were brought to Snathe by his subordinate Sontarans. Initially, Snathe almost beheaded the Doctor with a cutlass, but was persuaded to use him to find the Thanatos, which he planned to use to wipe out all pacifistic Sontarans and overthrow the leading members. However, when the Thanatos started to destroy Sontar due to declaring all Sontarans to be impure, Snathe snapped and threatened to slay Rose if the Doctor refused to stop it, only for Lerox to assault him to save her; the Thanatos subsequently interpreted this as evidence that the Sontarans were worth saving. Following this, Snathe fled, only to be attacked by some of the Inuk he and his troops had oppressed, who forced him outside in the middle of a Siverfire, killing him. (COMIC: The Betrothal of Sontar)

Personality
Snathe was an arrogant, ambitious soldier. He was bitter about being banished from the Imperial Sontaran Fleet, and saw Sontarans with pacifistic genes such as Commander Lerox as mongrels to be slain.

Initially, Snathe was ready to kill the Tenth Doctor in the belief that doing so would restore his glory, but was persuaded through his ego and instead chose to use him to find the Thanatos. He found the Doctor's humour and pacifism annoying. (COMIC: The Betrothal of Sontar)