Here's how the Sol system's litany of factions and planets line up in The Expanse season 6. Comparisons to Game of Thrones are not without reason, and The Expanse is absolutely packed with all manner of warring factions, each possessing their own goals, capabilities and cultures. Also like Game of Thrones, that landscape has shifted significantly through the seasons. The Expanse season 6 brings the Amazon era to a close, and presents one final opportunity for inter-faction peace.
When The Expanse began, the Sol system broadly divided into three categories. Earth and Mars (collectively known as the Inner planets) were considered the two major military powers, but they remained locked in bitter cold war as the Red Planet's weapons technology rapidly overtook its rival's. Those living on settlements elsewhere went under the umbrella term "Belters," but were structured into smaller factions appointing their own leaders, and making their own rules.
Since then, the Protomolecule has opened a gateway to other worlds, established leaders have fallen, and firebrand revolutionaries arose fueled by years of ill-feeling. All of these events have created a dramatically different solar arena in The Expanse season 6.
The Earth & Mars Coalition
Throughout The Expanse seasons 1-3, Earth and Mars bickered like any other siblings, but with nuclear missiles and gunships aplenty, this was far from a childish spat. Since the truth emerged regarding both planets' roles in the Protomolecule conspiracy, Earth and Mars have struck up a more peaceful dynamic, but The Expanse season 5 proved tensions remained when Earth's generals showed reluctance to point their sentinel missiles anywhere other than toward their neighbor. Moving into The Expanse season 6, those suspicions seem to have finally evaporated.
The reasons for Earth and Mars' improved relations are twofold. On one hand, Marco Inaros provided a common enemy for both planets to refocus their hatred. Belters caused trouble before, but none genuinely threatened the Inners' safety until Marco showed up. Secondly, neither Earth nor Mars finds itself in any sort of position to wage war against the other. Earth was already an economic mess in The Expanse season 1, but Marco's constant asteroid attacks across seasons 5 & 6 have brought civilization to the brink of destruction, with widespread famine, homelessness, and medical emergencies at home exacerbated by a war out in space. And Mars isn't faring much better. Their economy and military strength tanked thanks to an expensive war against Earth and the Ring Gate's boundless opportunities proving more tempting than Mars' long-term terraforming project. The planet took another embarrassing hit when defectors jumped to Laconia.
In The Expanse season 6, Earth and Mars are a united front - if only because both are too weak to stand alone. Main characters officially aligned include U.N. Secretary General Chrisjen Avasarala and her secretary/personal mercenary Bobbie Draper.
The Rocinante
Make no mistake, the Rocinante is fighting for Earth in The Expanse season 6, but the story's protagonist-carrier remains an independent vessel, technically speaking. The Roci crew now consists of James Holden (Earth - captain/pilot), Naomi Nagata (Belter - science/engineering), Amos Burton (Earth- mechanic) and Clarissa "Peaches" Mao (Earth - apprentice engineer), and they stood against Marco Inaros right from the beginning, confirming allegiance to Earth and Mars. Nevertheless, the Rocinante is still referred to as a privateer, and is essentially a contractor in the conflict. Despite intending to take reconnaissance jobs, the Roci has seen plenty of space combat against Free Navy ships since the war began.
Marco Inaros' Free Navy
The Expanse season 5 charted the Free Navy's evolution from one of many Belter factions into the Sol system's dominant force. Marco Inaros led devastating attacks on Earth, firing asteroids clad in Martian stealth tech to neutralize the planet as a threat. He also carried out attacks on Mars itself, and ensured Sauveterre's defectors would leave for Laconia, weakening the Inners further. Without interference from Earth and Mars, Marco was then free to begin his grand tour of the Belt, conquering one station after another between The Expanse seasons 5 & 6. The egomaniac now controls Ceres (the Belt's new capital), Tycho, Vesta, Prospero, Ganymede, and Iapetus. Marco's Free Navy has also absorbed almost every major Belter faction under his own umbrella, and effectively replaced the OPA, which served as the Belt's military rebel faction in The Expanse's early seasons.
Crucially, the Free Navy also holds Medina Station - the Ring Gate. This means no travel between worlds, no escape for the Inners, and no movement of supplies. Earth and Mars can't restock from their usual sources either, since Marco controls facilities like Ganymede, which are renowned for producing food.
Led by his flagship, the Pella, Marco boasts an ever-growing fleet of ships in his Free Navy, but has lost the ability to launch stealth-clad asteroids in The Expanse season 6. Other cracks are beginning to show too - many Belter colonies are going hungry, and the nepotism shown toward Filip (Marco's son) is rubbing key figures the wrong way. Marco's current aim is to consolidate his hold on the Sol system and establish the Belt as a dominant force long-term.
Camina Drummer's Faction
One of precious few Belter factions not currently aligned to Marco Inaros belongs to Camina Drummer. Before the Free Navy took control, Camina led a poly-amorous crew of Belter pirates on a small fleet on three ships - the Dewalt, the Tynan and the Mowteng. Despite bending the knee to Marco initially, Camina fought back. Partially due to her Rocinante connections, and partly out of admiration for her fallen friend Klaes Ashford, Drummer was inspired to go rogue and now leads a small band of Belters on the run from Free Navy rule. Aside from Drummer herself, the current crew includes Josep and, until very recently, Michio (a nod to the books' Michio Pa). The rest of her faction joined Marco in The Expanse season 5, taking the Mowteng with them, while the Dewalt was intentionally overloaded during battle with a Free Navy bounty hunter. Drummer is desperately low on more or less every supply imaginable, but has been biding her time, waiting for an opportunity to bring down Marco Inaros.
Golden Bough
Aside from Drummer's gang, Golden Bough is seemingly the only Belter faction (partially) holding out against Marco Inaros and the Free Navy. Their tenuous relationship began in The Expanse season 4, when a Golden Bough representative voted to let Marco live after the future villain was apprehended for an early, truce-threatening assault on Earth. Predictably, most of Golden Bough joined the Free Navy in season 5, but as revealed in The Expanse season 6, some were unhappy about the arrangement and struck out alone.
Drummer meets with the Golden Bough's Liang Walker in The Expanse season 6's "Azure Dragon," who reveals the Golden Bough rebellion resulted in Marco giving those who joined him the most humiliating jobs. Walker's Golden Bough have became disillusioned with their leader and began running side hustles, as well as skimming Marco's business. Now, it appears Golden Bough is prepared to align with Drummer to form a true Belter resistance.
Martian Defectors On Laconia
In The Expanse season 5, want-away Martians began colonizing the planet of Laconia beyond the Ring Gate. Unbeknownst to many on the Red Planet, a recon probe discovered remnants of massive Protomolecule ships languishing in the Laconia system, and stole Fred Johnson's sample of the blue stuff (the last of its kind) to take with them beyond the Ring, intending to activate the abandoned vessels. The final Martian defectors left for Laconia during The Expanse season 5's finale - aside from the Barkeith, which was mysteriously lost in transit.
Laconia has since gone quiet, but Cara's narrative in The Expanse season 6 reveals progress is quickly being made. While the colony's scientists continue studying their new surroundings and constructing a civilization from scratch, the military are continuing their Protomolecule project. If Amazon's adaptation follows the books, these scenes are taking place a few years after the Free Navy conflict in The Expanse's present timeline. Laconia's intentions aren't currently known, but those ships don't look especially friendly.
Ilus & Other Unknown Ring Systems
Laconia is far from the only colonized system in The Expanse, but very little has been revealed about the other worlds made accessible by the Ring Gate. Ilus is the only other exo-planet to appear onscreen, but hasn't featured since The Expanse season 4. No news is probably good news.
The "Dark Gods" (Protomolecule Destroyers)
Not strictly a "faction" but a major force in The Expanse season 6 nonetheless. While visiting Ilus in The Expanse season 4, Holden learned how, billions of years prior, the civilization that created the Protomolecule was wiped out by an unknown malevolent force. Now Earth, Mars and the Belt have activated the Ring Gate, those forces are stirring once more. Holden first felt how evil and devastating this entity could be when he and Elvi Okoye touched an anti-Protomolecule artifact, and the mystery aggressor then returned to spirit the Barkeith away as it transitioned through the Ring Gate. Only Holden and a select few others seem to realize something wicked is rapidly approaching.
The Expanse season 6 releases every Friday on Amazon Prime.