The head of the PLA's political branch

Baroness Apocrypha Quintelle, leader of the Coven of Thecula V, threw her home world into chaos (almost literally), rebelling against the Imperium. Her insurrection was put down by Inquisitor Vincorum of the Ordo Hereticus. She was freed by her confederates and nearly succeeded in slaying him during the escape. He chased her from system to system, eventually catching her in the city of Xyphonica, spiritual centre of life on Benq and possibly the whole of Devos IV. She was incarcerated, pending being shipped to the shrine world of Salem Proctor for trial.
Unluckily for Inquisitor Vincorum, this was as Chaux Na Mrr’see’s coup was unfolding. Baroness Quintelle’s crime was to have been born psychic and remained undetected until she began to suffer from an unfortunate case of episodic possession. On Devos IV, under sceptical, dismissive and hostile media focus, the Ordo Hereticus was put on trial, in the person of Inquisitor Vincorum. The charge was failing to protect the vulnerable Apocryhpa. Leading to an unfortunate chain of events and the unnecessary deaths of many innocent Imperial citizens on Thecula V and other places.
The Inquisition was found to be guilty and Inquisitor Vincorum was ceremoniously incarcerated in his own Incarcerator. Baroness Quintelle herself was allowed to flick the switch to begin the rite of purgation. On the continent of Benq, making the sign of the Aqilla in public is swiftly moving from a quaint idiosyncrasy, through public derision to cause for arrest.
Baroness Apocrypha Quintelle is now the Chief Political Officer for the Peoples Libertine Army. She sent Inquisitor Vincorum’s ashes to the Hospitallers convent. It was this threat that provoked the Mother Superior to call for aid.
As far as the New Republic are concerned, the cause of the arrival of the Cadian 144th LRRR can be directly traced to the Ordo Hereticus’ failure to guard Baroness Quintelle against deamonic possession. The PLA is only defending Devos IV against the warmongering Sisterhood and their lickspittle lackies from Cadia.