ComStar Civil War
Occurring in the early years of the Third Succession War, the ComStar Civil War was a conflict between those loyal to the paranoid and insane Primus of ComStar Dwight Kurstin and supporters of the First Circuit led by Gregori Hartford.
The Mad Primus
With ComStar suffering increasing economic pressures following the "Black December" Incident in 2877, in an attempt to secure the support of a conservative power-bloc on the First Circuit blocking proposed HPG transmission rate increases, in 2882 Primus Andrea Marteen met with this group and agreed to named Dwight Kurstin from their number as her successor to the Primacy. 
The remainder of Marteen's reign was relatively quiet until January 2901 when she was touring the capital of Caph beside Kurstin in a hover-limo, which was forced to swerve to avoid hitting some refugees crossing the road. The vehicle exploded after plowing into a building and all but Kurstin, who was able to escape moments before the explosion, died in the crash. The Primus's ROM security detail evacuated Marteen's successor to Terra and Kurstin was confirmed as Primus of ComStar shortly after. 
Kurstin's reign as Primus was clouded from day one after the investigation into the crash a raised number of questions including the fact Andrea Marteen died from a sharp blow to the neck, yet the shock-cushioning material of her heavily-padded limo's interior was not compromised prior to the explosion. While inconclusive at best, the investigation reflected poorly on the new Primus, a situation worsened when the enraged Kurstin publicly denied any involvement in the accident and ordered the two investigators arrested and later executed. 
The depth of his paranoia only increasing as the weeks went on, Kurstin ordered ROM to investigate several members of the First Circuit to see if in-fact they were behind the Marteen's death in an attempt to frame him. Matters became worse when Kurstin attempted to make his first appointment to fill a vacancy on the First Circuit, selecting his first cousin Dana Kurstin, mere Acolyte of ten months. While Kurstin insisted he was promoting her strictly on her basis of her abilities, several members of the First Circuit, led by Precentor Kari Marshall, directly implied that her appointment was purely based on her family ties to the Primus and vetoed her appointment.  
Kurstin's instability initially was known only inside the Blessed Order, but in the lead-up to the state funeral of Andrea Marteen word of these rumors and suspicions some how reached the leaders of the Successor States, with First Prince Joseph Davion and Captain-General Elisabeth Marik, herself a former Adept in the Order, refusing to attend Marteen's funeral. Now seeing enemies everywhere both within and outside ComStar in the wake of this public snubbing, upon discovering two young adepts were behind leaking the rumor, Kurstin ordered them both executed without trial, further damaging his already shaky support in the Order.
The Exiled First Circuit
The final breaking point was a particularly stormy session of the First Circuit where Kurstin directly accused a Precentor Kohler of plotting against him, answering Kohler's denials by branding him a heretic, dismissing the First Circuit and ordering ROM to take him custody. Three hours after the end of the session Kurstin sent a message to the extremely skeptical members of the First Circuit indicating that Kohler had died from natural causes while still in custody.  
Having lost all faith in the clearly insane Kurstin, the remaining Precentors of the First Circuit met in secret in the empty halls of the Court of the Star League at urging of Precentor Procyon Gregori Hartford to discuss their limited options. With ComStar law making no legal provision for the removal of the Primus from office on health grounds, and his direct control over ROM preventing them from physically deposing him, Hartford suggested their best option was leave Terra, both to see how Kurstin would react and to try and stop the spread of information of his condition in order to protect the reputation of ComStar. The First Circuit left Terra on April 20th.  
Infuriated upon learning of their departure, on April 30th Kursti sent what became known as the "Witch-Hunt Transmission", a one minute speech dissolving the current First Circuit, branding the members of renegade body heretics and decreeing that they be burned at the stake for their heresy. While Kurstin intended it to be sent to every HPG station in the Inner Sphere, the exiled First Circuit intercepted the message and Hartford responded by ordering the First Circuit HPGs to operate without central coordination from the Terran HPG, effectively imposing a Communications Interdiction against Terra itself.    
Now driven over the edge, Kurstin used JumpShip couriers to send orders to ROM to assassinate the First Circuit and eliminate any members of the Order felt to be disloyal to him, a bloody purge reminiscent of Conrad Toyama's Purification that rounded up the innocent and guilt in equal measure. Under the protection of some 100 ROM bodyguards, the insane Kurstin then proceeded to transfer his seat of office from Hilton Head to the Court of the Star League. Adopting the First Lord's throne as his own, Kurstin had the ashes of Conrad Toyama exhumed and engaged in conversations with the deceased Primus. In response to seeing their leader so mentally incapacitated, a number his bodyguards attempted to desert, only for Kurstin to have their bodies drawn and quartered as a lesson to those who might break faith with him.   
Even in the face of such dire threats, ROM itself mirrored the fragmentation of the Blessed Order between loyalist, rebels and those seeking to lay low and avoid taking either side, making waging an intelligence war difficult. With ROM's internal efforts hamstrung and the First Circuit's relatively successful attempts to prevents news of the Civil War leaking to the general public, by the fall of 2901 Kurstin set in motion Operation Winged Crusader. Contracting the services of three mercenary units passing through Terra and unaware of the isolated Primus's insanity, Kurstin assigned the mercenaries vintage SLDF equipment from ComStar's secret stockpile to arm them in preparation to assault and retake the First Circuit's HPGs by force.   
When word of Winged Crusader leaked to the exiled First Circuit and the Order as a whole, Kurstin's blatant attempt to use military force in contradiction to the will of Blake cost him yet more supporters. Having long feared that matters might come to this, Gregori Hartford activated his ace in the hole, smuggling a message back to Terra to a ROM agent known only as Saber.   
On January 3rd 2902, Saber entered the Court of the Star League, disabling all security systems and the two guards stationed outside the throne room, before shooting Kurstin through the head with a laser at point-blank range. Saber left no trace save for a copy of "The Word of Blake" lying on the throne room's marble floor.   
With even Hartford's fellow First Circuit shocked by the move, and the now leaderless mercenary troops standing down with Kurstin's death, the exiled Precentors of the First Circuit called for an immediate end to hostilities and requested a summit on Terra. Exceedingly brief, the First Circuit dictated terms of surrender to those who sided with Kurstin and selected Gregori Hartford as the new Primus of ComStar. Among Hartford's first actions was to orchestrate the most intricate cover-up operation performed by ROM, suppressing any evidence the ComStar Civil War occurred and fabricating documentation that Kurstin had simply resigned office, with no reference to his mental state.  
Elements of the fanatical Word of Blake would in fact cite the cover story as the true version of events, that while Kurstin lost touch with reality there was no all-out civil war, claiming that the entire conflict was invented by the secular ComStar as a ham-fisted means showing that disagreements such as that between the Word and the secular ComStar had occurred previously in the Order's history.
- ComStar, p. 34 - "Slow Change"
- ComStar, p. 35 - "Kurstin the Mad"
- Intelligence Operations Handbook, p. 104 "ROM - Brief History - Witch Hunts"
- Field Manual: ComStar, p. 12 "The Com Guards - History - The New Dawn"
- ComStar, p. 36 - "To Reign in Hell"
- ComStar, p. 36 - "Kurstin the Mad"
- ComStar, p. 37 - "Sword of Justice"
- ComStar, p. 37 - "Kurstin the Mad"