Telluis (more commonly referred to as Telluis the Betrayer) was an exiled Sontaran Colonel and the former leader of the Sontaran Elite Division around the 52nd Century. He was notorious for having avoided execution by his superiors after he was caught selling information to the Rutan Host. Banished from Sontar, Telluis resorted to mercenary work. Later, he fought and died in the Millennium War.
Telluis originally served as a communications specialist onboard the main warship of the Sixtieth Sontaran Battle Fleet, though his ambitious nature eventually led to him receiving several promotions until he gained the rank of colonel and was appointed the head of the Sontaran Elite Division, one of the most senior Sontaran squadrons.
Telluis would then spend seven years in the thick of the Sontaran's war with the Rutan Host, during which he was rumoured to have single-handedly killed four Rutans with his bare hands. On another occasion, he personally led the battle charge against the Rutans in a legendary battle that devastated an entire planet in the Veruna system.
However, after so many years spent in the forefront of the war, he soon became disillusioned with the Sontaran's cause, believing that the war would drive the Sontarans to the brink of extinction. Finally, after being denied a promotion that would have made him a general, Telluis decided to double-cross his superiors and sell information for the Rutans, hoping that once the Rutans began overpowering the Sontarans, his people would choose to negotiate a stalemate.
For five years, Telluis worked for the Rutans as their spy and infiltrator in the Sontaran ranks until he was caught giving the Rutans the stratagems to a planned bombardment on Ruta III. Captured and stripped of his rank and honour, Telluis was to be sent back to Sontar to be publicly executed. In order to shame him, his fellow soldiers gave him the title of "Telluis the Traitor", though a number of similarly derogatory titles were also given to him. However, en-route to Sontar, Telluis managed to break free of his captivity and escape in a scout ship.
With nowhere else to go, Telluis turned to the life of a mercenary, and retreated into the criminal underworld of Mutter's Spiral in self-imposed exile. Eventually, he managed to build up a formidable reputation as a freelance gun-for-hire, notorious for taking up especially risky jobs. Though he hired himself out to the highest bidder, he was unusually honourable for a mercenary in the fact that he would never betray an employer or abandon a mission.
He was known to be a frequenter of the seedy bar known as the Maldovarium, where he would often resort to heavy alcoholic drinking so as to drown out his sorrows. He was also familiar with the bar's owner, Dorium Maldovar, who would regularly supply him with information and rumours that would aid him on his missions.
Telluis would also regularly visit a bar in the Crab Nebula known as Raxas' Rest, whose owner, Scax Fel-Fotch Heppen-Bar Slitheen, would become a close associate of his. During one of his many nights spent drinking, Telluis unknowingly encountered the ninth incarnation of the Doctor, who identified himself as "John Smith" to avoid suspicion. After attempting to bring Telluis out of a bout of depression, the Doctor saved him from being attacked from behind by a drunken bystander before departing.
At one point, Telluis travelled to the entertainment world of Vegas 12, where he challenged an individual named Gantok to a game of Live Chess. However, he soon began losing the game, and in order to survive, was forced to barter his blaster gun for his life. Humiliated, Telluis left the planet in disgrace and bitterness. Not long after, Telluis replaced this weapon with a gun he stole from a Judoon trooper.
Telluis would eventually make the choice to become a Dalek Killer, a near-suicidal occupation that regularly pitted him against Dalek forces for heavy bounties. Though the occupation had originally been created by the Earth Empire in the 26th century as a form of punishment, many still required the skills as such hunters to eliminate prominent Dalek threats. After surviving five missions, Telluis' reputation shot up dramatically, and he became heavily sought out by a number of Dalek-opposing organisations. However, he chose to retire from this lifestyle and return to the role of a regular mercenary, aware that his current occupation would inevitably kill him. By this time, Telluis had lived an extraordinarily long Sontaran life of seventeen years.
An old and sickly Sontaran was seen dying on a battlefield in 150 million B.C. shortly before the Euterpians and the Greld destroyed the entire galaxy to eliminate a thousand of the Mad Mind's fleets during the Millennium War. The Sontaran himself claimed to have been time-displaced by the Ministers of Grace to help fight in the war. Though his identity was never discovered, records held by the Ministers confirm that this was indeed Telluis, who had been chosen to help fight the Mad Mind due to his success as a mercenary.
Telluis was an ambitious and cunning individual, notorious for his excellent skills as a military tactician. However, he was not committed to the Sontaran cause, feeling that their war with the Ruran Host would eventually drive them to extinction. This made him bold enough to betray the Sontaran Empire to the Rutans and sell important information to them. Though he despised them as much as any other Sontaran, Telluis felt that if the Rutans began to win the war in a way the Sontarans could not counter, they would be forced to negotiate peace.
Perhaps because of his treachery, Telluis had a paranoiac fear of disloyalty from those under his command. He was, however, a fearless warrior, being willing to face uneven odds without hesitation, which made him a powerful foe. After his betrayal, Telluis became particularly defensive of what was left of his pride, and even as a mercenary, operated by a rugged code of honour. Though he found mercenary work engaging, Telluis did not find it quite as savoury or invigorating as his days as an officer in the Sontaran Empire.
Like all Sontarans, Telluis was extremely passionate about warfare and combat, though he preferred to be in a role of power over the role of a soldier. He often chose to face his opponents "open-skinned", and rarely wore his battle helment. He was more than willing to die in combat, and felt death on battlefield would be a "marvelous" fate. Because of his love of battle, Telluis had trained himself to become an excellent marksman and capable in both armed and unarmed combat.
Telluis' self-imposed exile often had had a very lasting effects on him, and he had entered a mild depression by the time he became a Dalek Hunter. He had also resorted to heavy drinking in order to ease his melancholia, though this eventually resulted in him suffering from severe alcoholism. Despite being a traitor to his own kind, he often enjoyed reflecting on his military career, and he was very proud of his Sontaran background.