I had the idea of the Dynasty being awoken at the point of the Heresy. a few hundred still-loyal marines of the Emperor's Children being hunted by the Imperial Fists wake the Crownworld & surrounding Tomb Worlds with their conflict. The Necrons basically kill them both down to a few HVIs who get Cronified to serve the Dynasty, and steal all their gak (a battlebarge being the only notable one, thanks to the EC). The Dynasty moves its main foundaries of the Crownworld onto the Battlebarge, repurposing it as a Tomb Ship, and then scram to the Ghoul Stars. They then wait there until the Tyranid incursion there, so kick its arse and leave again. after being told by the Crypteks analysing a Hive Tyrant's corpse that they must be drawn to the astromonicon, and that theres another fethtonne of the bugs on their way, the Dynasty decides to take out the thing drawing them here, as they know the other races will never cease fighting enough to fight the Nids off.

Thios boils down to they are going to try and march up to the Imperium's front door and Glass Earth. Probably free the Void Dragon while they are there and throw it at HFL.

Founded in M36, the Iron Serpents are an offshoot chapter of the Iron Hands. Taking the love of new and existing technology to alarming levels, they tried to give their wounded Chapter Master a fully mechanical body encased in Artificer Armour, rather then in a Dreadnought, so as to not loose functionality. Mechanicum goes mental with them, 'breaking the rules' and shiz. to kick back at them, Serpents break the will of the Machine SPirits in their vehicles, using AIs instead of them (as in modern 2013 level military, just more grimdark). Mechanicum then basically goes to the High Lords "get them to go and kill themselves on a crusade or we will kill them right now". to avoid loosing the Mechanicum's trust, the High Lords do exactly that.

Radical Inquisitor comes along and enlists the Serpents as his personal hitmen, and sends them after a Chaos Warband known only as the Souless. They stay at it for aeons, killing off pockets of other traitors who ar incorrectly ID'd, as they have to follow every lead. Eventually they find the Souless whilst they are in bvattle with the Necron Dynasty over possession of the Heresy-era battlebarge. Under orders to kill the Souless, the Serpents drive the Traitors off, but are disabled by the Necrons. the Chapter Master manages to barter his way into the Necrron fleet, discarding all ties to the Imperium (bar the Inquisition order, as they don't want to have to fight the GKs) and pledging the Chapter's manpower and only starship of note - a Battlebarge - into the Necron's fleet in return for their own lives being spared. The Phaeron of the Dynasty accepts the offer, intending on using these Astartes to his own advantage

The Kinlad Liberation Army

During the closing years of M41, perhaps some of the darkest in mankind's history, a mass rebellion (Relatively speaking. In the grand Imperial Schemes it was significant for a rebellion but, at best, too minor of a conflict to be really mentioned) broke out in the Ultima Segmentum that devastated many worlds and resulted in trillions of deaths. The Rebellion has several names in Imperial Records depending on the source. It's most common name, though, is the Oronos Civil War.

The KLA can trace it's roots to a holy war called the Greywatch Crusade. The Greywatch Crusade was a minor campaign waged against the powerful xenos of the paradise world of Greywatch. The Xenos, along with their well armed and mind controlled human lackeys, were utterly crushed underneath the massive heel of the Imperium though at a great cost. The Imperial battlegroup who had conducted the war was reduced to 30% fighting strength in total. The army was exhausted and low on everything that an army could be low on. However, to the Departmento Munitorum, they had a 10 million strong fighting force equipped with Superheavy Tanks, Titans and it's own attached fleet. After a 2 month "rest" and a massive resupply, the battle group was sent to the partially Tau controlled Sector of Oronos to restore Imperial dominance in the area in the name of the Emperor.

Thanks to the army's fighting experience, inspired leadership, the assistance of partisan groups in the Tau sector, several Space Marine chapters and a Sisters of Battle detachment the Tau were defeated quickly. It was then decided by the Munitorum that the Battlegroup would be retired and it's assets reassigned elsewhere. However, fate would have other plans. 1 month into the occupation a wave of anti Imperial sentiment surged on the Hive World called Acrocopia. This dissent was being headed by a death row escapee known as Karshoff, a skilled orator and politician. The dissent turned into full fledged rebellion after reports of citizens being rounded up and shot by the occupying Imperial forces. In truth, it was the work of one Inquisitor Harland attempting to stem a growing Slaaneshi cult from becoming too influential. However, the people of Acrocopia had lived for years without Imperial rule and were unused to such things. The incidents were turned into anti Imperial propaganda which sparked the already dissatisfied people into taking up arms.

The Inquisitor barely escaped with his life after the world fell to rebel hands. Worse yet the floating Imperial Fleet above, who was unaware of the rebellion going on below due to clever rebel tampering with the Imperial comms network, found itself besieged by the rebels. Rather than citizens armed with surplus Tau weapons and whatever stub gun they undoubtedly had they instead found Imperial Guard turncoats boarding their ships. Karshoff had inspired the veteran warriors to turn on their former masters, decrying the Imperium as a rotting state who wished to see all suffer and toil for their lives amongst other such claims.

With an army and a fleet the rest of the system fell to Karshoff including the arid world of Kinlad. It was decided that this planet would house the new government due to it's former significance to both the Imperium and the Tau. It was a Tau Sept before the invasion and thus a major target. Since Karshoff was a Gue'vessa commander the world had personal significance to him as the center of the system. Thus many new cities were built, foritifcations were erected and recruits, be the veteran ex- guardsmen or green novices, were mustered. 100 Shock Armies, self contained invasion forces that relied on mechanized infantry and armored support, were formed from these recruits. The ex-Guardsmen were often assigned as mentors and leaders to the far more numerous new guys. It was mandated that each shock trooper would be amongst the best equipped and trained soldiers that have ever been. Though the final product was far from these lofty goals they were better equipped and trained than their Imperial counterparts.

Each Shock Army ventured out to enforce Karshoff's will across the sector. In the beginning the KLA enjoyed great success abroad and many unprepared worlds were swept in a tide of rebellion. However, when the Imperium mustered it's response the traitor's momentum slowed. On some worlds the Kinlads defeated the organized resistance and on others they were either stopped or beaten back. 1st Shock Army, for example, won a significant victory on the civilized world of Kalori defeating several first founding Space Marine chapters and inspiring loyal Imperial Guardsmen to turn.

As the war progressed, though, it was becoming more clear that the Shock Army program was becoming unfeasible as supplies ran short. Chimeras couldn't be produced fast enough to replace losses and there was a significant shortage of Plasma guns. In addition, what Shock Troopers they did have were dying far too fast to be replaced with troopers just as good. What was worse is that the experienced soldiers that had made the Shock Armies what they were were mostly dead by now. Currently the Kinlad Liberation Army is considering to construct more "traditional" forces along the lines of Imperial Guard regiments as they have loads of recruits that are eager to fight but weren't good enough to become Shock Troopers. In addition, the Tau Empire, wishing to impress the rebels with the power of the great good in hopes to absorb the Kinlads into their fold, has pledged some forces to assist their cause. It will be determined by the mettle of the brave Kinlad soldiers, the leadership of their heroes and a lot of luck whether the rebels will have independence or whether they will die out like so many before them.