The Sovereignty of Kahless was a Klingon insurgency composed of rogue minor houses and led by the Great House of Ma'rek from 2388 to 2391. Ma'rek, the leader of the house has been known throughout the Empire as someone who has fell into dishonour. After being discommendated from the High Council, Ma'rek went into exile in an unknown location outside the Empire with a small group of his dedicated followers.

In early 2388, Ma'rek returned with a new found appreciation for the old ways, his devotion to Kahless and his unwavering opinion that Klingons had gone soft and stale in their relationship with the Federation. Upon his return, his brother Hod'js returned control of his house and officially declared for Kahless as Emperor of the Empire, a position that Kahless already held but in a ceremonial capacity.

In 2389, the Sovereignty of Kahless invaded Federation space across three sectors. The Sovereignty maintained control over this space, as well as numerous systems within Klingon space, until 2391, when Starfleet and the Klingon Defense Force jointly retook their worlds as part of Operation: Gatecrasher. Ma'rek was killed and most of the Sovereignty's leadership were dead or scattered.

Following the Sovereignty's defeat, many of their surviving ships and crews aligned themselves with the House of Mo'Kai.

Timeline

Klingon Civil War (2367/68)

Shortly after the Civil War caused by a contested Rights of Succession in which then Captain Jean-Luc Picard was Arbiter, many past dealings of House Duras were also linked to other prominent houses within the Klingon Empire. On review of the evidence it seemed wherever House Duras had acted dishonorably, House Ma'rek was also close in support. Due to crimes against the Empire and the rightful Chancellor, House Ma'rek was disgraced. However, they were too powerful to fully dismantle or even remove from the High Council, and they remained in a place of power for the following decades.

Marek's Early Insurgency (2379)

After the Klingon Civil War, Ma’rek attempted to gain influence and power through both traditional means and more underhanded means. When it was discovered by Klingon Intelligence that he had been working with Romulan agents in an attempt to secure an alliance, he was publicly dishonored and banished, leaving his brother Hod’js as the leader of the House. Starfleet intelligence disputed the authenticity of the accusations at the time, due to its proximity with the Shinzon Incident. The dissolution of the Romulan Senate and the coup by Shinzon greatly weakened Romulan reach at the time, and it is unlikely that the Tal’Shiar or other agencies would have been willing to risk opening talks with an upstart Klingon House.

Attack on Utopia Planitia (2385)

The Attack on the Romulan Evacuation Fleet on Mars left Starfleet in turmoil. With massive casualties and the total loss of the largest fleet assembled in Starfleet history, reverberations were felt around the Federation. Throughout the Beta Quadrant, ships were recalled to Earth, and the prospects for reinforcing the area of space between Klingon and Romulan space were slim. With even old mothballed ships out of the question, the ability of the Federation to patrol the region was greatly diminished, leading to lower levels of intelligence gathering and an inability to react swiftly in the coming years. Eventually, this power vacuum, however small it may have seemed at the time, provided ample grounds for the insurgencies that would define the region in the late 2380s.

Marek's Return (2387)

Ma'rek returns from his banishment during the middle of the year. Somewhere along the way he claims to have had a profound religious experience. Ma'rek makes waves across the Klingon Empire with open and active support for Kahless to return to power as Emperor rather than a figurehead put in place by the High Council. He cites ancient Klingon claims on Federation sectors on their coreward border, as well as a need for a more direct line to the territory of their ancient enemy, now badly weakened after Romulus’s destruction. This is used as evidence of the Empire’s descent into weakness, a grim future for the Klingons, and the High Council’s lack of understanding of what it truly means to be a Klingon. This appeals to many of the more conservative houses and those who have lost standing in the modern Empire, though generally it does not sway public opinion. Among Ma'rek's allies were the Houses of Si'tac and Q'ras, who had built battlestations in many key Klingon systems and had the capability of seizing them instantly.

The Sovereignty of Kahless's Early Successes (2388)

While at first Ma'rek seems to struggle to find much backing, his working behind the scenes allows him to build a force equal to roughly a tenth of the Klingon Defense Forces. These numbers, however, were greatly underrepresented by Klingon and Federation intelligence, who continued to dismiss the possibility of a large scale threat. Numerous raids occurred in Klingon space and adjacent Federation sectors, especially on the coreward border. While Klingon Defense Forces were successful in repelling some small raids, their dismissive attitude towards the threat allowed for a large buildup of forces under the Sovereignty of Kahless. Once they realized the threat, they attempted to quietly handle the situation, only to have their fleet repelled by a smaller Sovereignty task group.

A brazen victory for the Sovereignty further eroded some Houses confidence in the High Council, leading to continued movement of Imperial Houses to the side of the Sovereignty. It was around this time that Starfleet attempted to provide aid, but those attempts were largely disastrous - and included the destruction of a small number of prominent Starfleet ships operating in the region.

Invasion of Federation Space (2389-2391)

In late 2389, confident that Starfleet was incapable of fielding a response so soon after the destruction of Utopia Planitia, Sovereignty ships crossed the border and invaded Federation space in three sectors. Fifteen starships and seven orbital facilities were destroyed, and Klingon troops landed on eleven colony worlds. The Sovereignty also began harassing member and protectorate planets. Cloaked marauders dissuaded merchant and even aid ships from reaching annexed planets. Starfleet’s ability to react was limited.

Over the next two years, the Sovereignty maintained near total control of its annexed systems. Additional forces provided from unknown benefactors permitted their influence to expand. Three more Federation colonies fell, and one member world was annexed.

The Klingon High Council, recognizing this invasion as the action of an extremist faction against the wider interests of the Empire and its allies, condemned the Sovereignty and refused to accept control over Federation worlds. The Sovereignty was forced to defend its holdings against both Klingon and Starfleet ships.

Meanwhile, the leadership of the House of Mo'Kai grew disenchanted with the rulers of the Klingon Empire. Recalling the era when T’Kuvma united the Houses of the Klingon Empire against the Federation, the House of Mo’Kai sought a return to the old ways of Klingon supremacy against its enemies. Seeing a kindred spirit in Ma’rek and agreeing with the actions taken by the Sovereignty to return the Klingon Empire to its roots, House of Mo’Kai began surreptitiously supporting the Klingon extremist faction. In 2391, in an effort to further dissuade Starfleet from attempting to take back their worlds, ships loyal to House of Mo’Kai, but publicly claiming allegiance to none, attacked and destroyed the Xavier Fleet Yards.

Operation: Gatecrasher (2391)

Operation: Gatecrasher was a joint operation between Starfleet and the Klingon Defense Force to liberate Federation worlds from the Sovereignty of Kahless and defeat the Sovereignty once and for all. A large portion of Task Force 93 launched an assault on several occupied colonies, while Klingon ships attacked more still. This prompted the Sovereignty to reinforce the systems under attack, slightly loosening their grip on the three worlds where most of the Sovereignty’s leadership resided (Mempa, Narendra, and Occupied Faltan).

Meanwhile, the Task Force's fastest ships prepared their actual plan. Once the Sovereignty was engaged, the swift ships, with Imperial support, struck the less-defended headquarters worlds. Within hours, Ma’rek was dead and most of the Sovereignty leaders, including the leaders of the Houses of Si'tac and Q'ras, were either killed or captured. Without leadership and coordination, Sovereignty forces were left in disarray. Though casualties were heavy, the Sovereignty was defeated.

A New Threat (2391-2399)

A number of Sovereignty ships, including some leaders, survived Gatecrasher. They were welcomed and harbored on the Mo'Kai throneworld. Sensing common goals of restoring Klingon greatness by whatever means necessary, a call was stealthily put out to any and all surviving members of the Sovereignty to regroup at Mo’Kai.