The years following the Clan invasion saw a great deal of change and upheaval throughout the Inner Sphere. Shortly after the Treaty of Tukayyid was signed, Hanse Davion died of a heart attack, leaving his wife Melissa as sole ruler of the Federated Commonwealth.

On the other side of the Inner Sphere, Capellan Chancellor Romano Liao was assassinated, leaving her son Sun-Tzu to take her place on the Celestial Throne. He quickly sought to ally himself with the Free Worlds League, through an engagement to Isis Marik, daughter of Captain-General Thomas Marik.

A few years later, Theodore Kurita succeeded his father Takashi, as Co-ordinator of the Draconis Combine. In the Lyran half of the Federated Commonwealth, Ryan Steiner began calling for the Isle of Skye region to be given independence.

Long-simmering internal differences within Comstar finally came to a head. The more militant members formed a splinter group, calling themselves Word of Blake and relocating to the world of Gibson, in the Free Worlds League. Captain-General Thomas Marik, a former Com Guard officer, welcomed them with open arms.

The beginning of the end of the Federated Commonwealth came with a very sinister turn of events, when on June 19 3055, Archon Melissa Steiner was killed in a bomb attack at a charity event she was attending. No suspect was ever found. Ryan Steiner, having successfully stirred up anti-Davion feelings in the Skye region, wasted no time in capitalising on this, by accusing Victor Steiner-Davion of plotting his mother's death, so he could claim the Commonwealth throne for himself. He duly got his wish, as the region, already simmering with separatist fervour, erupted in open rebellion. Victor's sister, Katherine, attempted to act as mediator, between her brother and Ryan Steiner, but with little success.

Events rapidly spiralled out of control from that point, as Galen Cox, aide to Victor and lover of Katherine, was killed in the bombing of a Solaris hotel in April 3056. Katherine herself narrowly missed becoming a casualty in the attack. Four days after that, Ryan Steiner fell victim to another unidentified assassin, although suspicion fell on Sven Newmark, a Rasalhagian expatriate who had seved as Ryan's aide. However, many suspected Victor had ordered the assassination, because of Ryan's allegations regarding Melissa Steiner's death.

In an effort to ease the rising tensions in the Lyran half of the Commonwealth, Victor declared the Lyran world of Tharkad and the Federated Suns world of New Avalon, co-capitals of the Commonwealth. He relocated his government to New Avalon and left Katherine to establish her own government on Tharkad, also appointing her as Regent. This, coupled with Ryan's death was enough to quell the Skye rebellion, at least temporarily.

When Victor arrived on New Avalon, further trouble greeted him, as he learned Joshua Marik, son of Captain-General Thomas Marik, was succumbing to leukaemia, despite the best efforts of the top medics at NAIS. The Federated Commonwealth was still desperately short of military equipment and the Free Worlds League, relatively unscarred by war, was best placed to supply them. Relations between the two states were on shaky ground, but Victor could not afford to lose the support of the Captain-General. With desperate times calling for desperate measures, he arranged for the dying Joshua to be replaced with a double. However, Thomas Marik got wind that something was wrong and he ordered steps to be taken to confirm his suspicions. Consequently, in the autumn of 3057, a raid was staged, with operatives dressed as Capellan commandos, in an attempt to kill Joshua's double. Although they did not succeed, just days later Marik publicly declared that the child on New Avalon was not his son and that he could prove this, before ordering FWLM troops into the Sarna March of the Federated Commonwealth.

Victor's sister, Katherine, publicly condemned her brother's duplicity, ordering all Lyran troops to withdraw to the Lyran half of the Commonwealth. Severing ties with the other half of the realm and announcing the formation of the Lyran Alliance, she declared her state neutral. Meanwhile, Capellan Chancellor, Sun-Tzu Liao, also took the opportunity to send troops into the Sarna March, to reclaim worlds lost during the Fourth Succession War.

As these shifting alliances and escalating conflicts threatened to engulf the entire Inner Sphere in war once more, the political infighting among the Clans also came to a head. The Jade Falcons in particular, refused to acknowledge the Treaty of Tukayyid and looked for any excuse to break it, regularly staging raids into Lyran territory. This led to a clash with the Warden-controlled Clan Wolf, which ended badly for the Wolves, who also had to contend with the rising Crusader faction. Khan Phelan Kell, former Kell Hound mercenary and bondsman, led the Warden faction to the Kell Hounds' homeworld of Arc Royal and formed Clan Wolf-in-Exile, while the Crusader faction and continued to fight a losing battle against the Falcons, which did a great deal of damage to both Clans and became known as the Great Refusal War.

Both the Successor State and Clan wars ended, after a series of unexpected events. With the FWLM having recaptured the worlds lost in the Succession Wars, Thomas Marik signed a peace treaty with the Federated Commonwealth. Unwilling to continue to fight alone, the Capellan Confederation also ended hostilities. In the Lyran Alliance, the Kell Hounds established a buffer zone against the Jade Falcon Occupation Zone, known as the Arc Royal Defence Cordon, centred on the world of Arc Royal. Meanwhile, the Falcons and the Wolves, having weakened each other so badly in their struggle, agreed to merge, to avoid either of them being Absorbed by other Clans. This arrangement didn't last long, however, as the Wolf faction soon felt ready to fight a Trial to win their freedom. They succeeded and once again became an independent Clan, known as Jade Wolf. It took the death of Falcon Khan Elias Crichell, at the hands of Vladimir Ward, to give Ward the political clout he needed at the Clan Council, to shed the "Jade" part of the name and proclaim himself Khan of the reborn Clan Wolf.

While everyone's attention was diverted by the FWL / Capellan invasion of the Commonwealth's Sarna March, the Word of Blake seized the opportunity to strike at Terra. Catching Comstar completely off-guard, the invasion was swift and overwhelmingly successful, forcing Comstar to retreat and relocate their headquarters to Tukayyid. The Blakists accomplished this by moving units from the FWL, to worlds in the Chaos March. With faith in Comstar at an all-time low since the Clan invasion, many of these planets were calling for mercenary aid in settling local disputes and protection from piracy. The Blakists stepped into the breach, displacing the Com Guard units based there, without incident. Terra was left particularly vulnerable, when Brion's Legion, a mercenary unit which had made up nearly half the Terran Defence Force for many years, suddenly chose to defect to the Blakists and took up an assignment in the Chaos March. WoB then learned of Comstar's plan to employ the 21st Centauri Lancers in their place and sent a unit, masquerading as the Lancers. They were able to maintain the deception until the full invasion force was in place, leaving the remaining Comstar forces on Terra hopelessly outnumbered. The Blakists struck in mid February 3058 and by early March they were in full control of the planet.

While this was ongoing, the Jade Falcons launched further attacks into the Lyran Alliance, capturing several worlds, until they were finally defeated on Coventry. These raids were originally conceived as a show of strength, to prove the Falcons were still viable as a Clan, after the Great Refusal War, but they were to have far greater repercussions. The Falcons came very close to victory on Coventry, but were forced to redeploy their forces when Clan Wolf chose that moment to strike at worlds in the Falcons' Occupation Zone. The Lyrans were also aided by the arrival of a coalition force, led by Victor Steiner-Davion. Even with this shift in odds, the Falcons fought with their customary ferocity and it quickly became apparent that neither side would achieve victory without a long and costly battle. Victor, using his knowledge of Clan customs, offered the Falcon Khan Marthe Pryde an honourable withdrawal or hegira allowing her to leave without further losses, which she accepted.

This success resonated with the leaders of the other Successor States and they realised that their common enemy could be defeated if they co-operated. Before the year ended, they would band together, plan and execute the largest military operation since the fall of the Star League, to wipe out an entire Clan and end the threat of invasion once and for all.