"By the authority I bear in the God-Emperor's Name, you are charged with cowardice in the face of the enemy, of gross and treasonous negligence in the employment of His warriors and His resources, and of base incompetence of command. For such crimes, only the Emperor may pass judgement, and thus I condemn you to death that you may face His scrutiny."
- —Lord Commissar Vance Theren, before the execution of Colonel Alastayr Vone
Theren is currently the head of the so-called "Triumvirate" comprised of himself, General Derian Arkelius, and Lord Admiral Anastasia Arkelius that has taken command of the Orpheus Salient of the crusade in the wake of the death of General Mikal Curas.
He is also the mastermind of the "Great Deception" the three have perpetrated to not let any of the men and women fighting in the Orpheus Salient know that Curas was killed by the Tyranids until his replacement can arrive from the crusade's High Command.
The most senior Commissar in the Orpheus Salient, Theren has presided over matters of military discipline since the first day of the salient's foundation. A veteran of many conflicts, Theren has served both on the ground alongside the Astra Militarum, and as a Fleet Commissar with the Imperial Navy, giving him valuable experience in a variety of theatres of war, and making him an ideal choice for such high authority.
His oversight of all Astra Militarum and Imperial Navy activities within the salient is carried out through the means of thousands of lesser Commissars stationed aboard starships and deployed within Astra Militarum regiments.
He was assigned to the Achilus Crusade from the outset and was attached as a liaison to General Mikal Curas' staff. A dutiful and honourable man, Theren does not suffer the wasteful use of the Emperor's armed forces, regarding the lives of the Emperor's servants as something not to be expended frivolously or rashly. Indeed, quite at odds with the archetypal image of the Commissar, Theren cares about the soldiers under his authority.
This has caused him to clash with the generals under his jurisdiction on several occasions, even going so far as to veto the battle plans of General Derian Arkelius more than once, and having executed several senior Astra Militarum officers for negligence over the years of the Achilus Crusade.
Further, he has reprimanded several of his subordinate Commissars for being overzealous in their punishments. The lives of the Emperor's servants are valuable and it is the responsibility of their leaders to ensure that the dutiful efforts of even the least of men are employed wisely, as Theren is swift to point out to his subordinates.
In spite of this atypical outlook, Theren is a stern disciplinarian, having established a collection of penal companies in order to deal with those who step out of line, and commandeering a special battalion of veteran troops to serve as military police, as he has found that squads of exceptionally disciplined troops, unbound by regimental loyalty, make effective enforcers.
Theren's respect for the lives of his troops became apparent to the other two members of the governing Triumvirate of the Orpheus Salient when he rewrote the defence plan for Treyan upon seeing General Arkelius had called for over one million Imperial Guardsmen to be sacrificed as bait to bring the Tyranids of Hive Fleet Dagon into a specified kill zone.
Part of the Achilus Crusade from the very start, Theren served closely with General Curas, and he held the general in high regard almost from the outset.
The death of General Curas at the hands of the Tyranids hit Theren hard. While they could not be considered friends, the two men had a mutual respect for one another and General Curas would often take Theren into his confidence about private command matters. Curas' death was an emotional blow to Theren, though his stern demeanour will not allow his acute sense of loss to show.
In the wake of Curas' death, Theren was the source of the plan designed to replace Curas in command of the Orpheus Salient without news of his detah becoming public in such a way that it would demoralise the crusaders.
Theren's plan, later called the "Great Deception," was to inform the other salient commanders of General Curas' death at the hands of the Tyranids, but with communication blackouts he knew that it could take Terran years for such a message to be received and years beyond that for a response to be sent back.
During this period no one beyond Theren, the Arkelius siblings and the crusade's High Command was to know of the death of General Curas until a replacement had been sent. In the meantime, and to keep the discipline and morale of the Orpheus Salient at workable levels, Theren proposed that a "Triumvirate" be formed to command the salient.
General Arkelius would be in command of all ground operations, Admiral Arkelius would be in command of all naval actions, and Lord Commissar Theren would play the mediator, as well as having final say over any disagreements that cropped up.
Now commanding from the flagship of Battlegroup Cerberus, Lord Commissar Theren is able to effectively deceive the rest of the ranking members of the Astra Militarum and Imperial Navy by combining his authority with that of either one of the Arkelius siblings. The word of a lord commissar backed up by either a lord admiral or a general is something no lower-ranking officer would dare question.
As the orchestrator of the Great Deception, Lord Commissar Theren is constantly on the lookout for signs that one of the two Arkelius siblings is plotting his downfall.
Without his iron discipline keeping the rank and file in line, the Orpheus Salient would be lost. His relationship with the Deathwatch is strong since, as a commissar, he always appreciates when a walking morale booster shows up on the field of battle.
A devout servant of the Emperor, Theren cannot help but regard the Space Marines with due reverence, and long years of service within the Jericho Reach, interacting with Space Marine commanders, has given him a deep respect for their abilities, and the morale-bolstering effect their presence can have.
Given the current state of the Orpheus Salient, he is ever willing to stand in support of the Space Marines and to accept their aid in fighting back against the Tyranids.
He has begun to doubt the teachings that have defined his life in the face of an enemy unlike any he has ever faced. In spite of this, Theren is one of the few individuals holding the Orpheus Salient together, his discipline and sense of duty maintaining order in the most terrible of circumstances.
The deception maintaining the illusion of General Curas' continued service was Theren's idea, and he maintains control over it, mediating between the Arkelius siblings who form the rest of the Triumvirate, and providing overall command in spite of their familial rivalry.
Amidst all this, he liaises with Space Marine forces within the salient, cooperates with the Deathwatch, and handles much of the inter-organisational politics that so frequently blights Imperial operations, wrangling with the demands of the Administratum, Adeptus Arbites, Adeptus Ministorum, and Adeptus Mechanicus, while endeavouring to win an extremely costly war.
In short, it is Theren's iron will that is the greatest factor in both the deception that General Curas still lives, and rallying the crusade forces that the general once commanded.
It should come as little surprise that Theren seems withered and exhausted to those who meet him in person. The cost of the Orpheus Salient's seemingly inexorable collapse weighs heavily on any man, and like his compatriots in the Triumvirate, the strain is taking a toll.
Amidst this pressure, Theren is gladdened by the increased Space Marine presence within the salient, and the more widespread deployment of Deathwatch Kill-teams, for every Space Marine who stands beside the mortal guardsmen and shipsmen of the Orpheus Salient lessens the weight upon his shoulders and those of every officer under his command.
- Deathwatch: The Achilus Assault (RPG), pg. 142
- Deathwatch: The Jericho Reach (RPG), pp. 137-138