Huge fan of Twilight Imperium.

Got my first 5 players Rex game yesterday evening as the Federation of Sol, lucky enough to hold the Imperial Palace and grasp Mecatol Power South on the first turn. Allied with the Hacan chap as soon as possible (3rd turn), then dug in as only a Sol could for the rest of the game. Easy victory, shared with my leonine friend since we chose to skip the Betrayal Card option (it was our first Rex game ever).

Any suggestion on how to prevent the Sol/Hacan Axes from winning the game?

Please consider that the Hylar player supported us for 2 turns and left the alliance due to total madness, and the Lazax/Letnev counter-alliance met serious problems when faced by our combined special abilities.

Thanks to all!

Neither has a battle ability, so you beat them the same way you beat anyone else: challenge them in a stronghold and play the right cards with a safe leader and enough tokens to back it up.

I wouldn't really even consider it a particularly strong alliance (going only by their powers, I mean, it obviously worked for you two based on your situation). The Hacan don't need to go after influence on the board due to their ability, so the Sol ally advantage doesn't help them often, and the Hacan ability is not often necessary for the Sol since they deploy free (and if you're just holing up in your alt-win territories, it's definitely useless).

The only advantage they tend to give each other is Turn 8 safety. You can both stall together without worrying about the particulars of who's in what stronghold.

Thank you for your ready reply.

But tell me, please, what if the Sol player sits like a hen on the Imperial Palace and Mecatol Power South, while his Hacan ally roams the board unpunished, harvesting influence and stockpiling it in a sort of denial tactic against the other players?

What if the Sol/Hacan Axis wins the support of a combat-oriented race like the Hylar or the Letnev? My concern is that a triple alliance like this could easily manage to hold on till the end of the game, thus fulfilling the Sol or Hacan Special Victory conditions.

Please keep in mind that my experience sums up to only one game, so I'm honestly just wondering..

There isn't some trick strategy. You have to beat the Sol at one of those strongholds, that's all there is to it. The Jol-Nar should know what cards are needed, so you can always ask him for advice of Sol/Hacan are such a threat that you need the rest of the players to cooperate. If someone sits like a hen, slaughter them like you would a hen, unless you're vegan, in which case I don't know what to tell you. If you guys were trying to defeat the Sol at those strongholds and failing, then either the Sol player was just really on top of his game that day, or the opposing players just need to keep pressuring him with battles every turn. No player can keep up against that every turn every game.

One thing is, I think you might be underestimating the combat effectiveness of Lazax/Letnev. Not only do they have a lot of traitors, but they (Letnev in particular) should be buying tons of Strategy cards. As Adam says, they'll be especially powerful if they can get either Jol-Nar (or Xxcha, for that matter) to help...although if they make a formal alliance out of it, it can be a little hard to avoid a default victory when you need to take all 5 strongholds. And if Hacan is grabbing all the influence while Sol defends two strongholds, Sol should be underequipped and, pretty soon, will have a hard time fielding enough troops to defend them (depending on circumstances, that is; Hacan can't normally give Sol influence, but they might get lucky and hit a temporary ceasefire at just the right time, but even so, he can only recruit 5 units per turn, and at considerable expense)

Mind that you're running combat correctly. The WINNER loses units dialed, the LOSER loses everything . You didn't explicitly say anything about doing that wrong, but if you were it might go a long way towards explaining why you think Sol is so easily capable of covering two strongholds by his lonesome.

Honestly, if this was just your first game, I wouldn't go off the rails looking for a way to "beat' this "formidable alliance." It worked out once, among a group of inexperienced players. Just keep playing, and see if the same alliance continues to win after ten or twenty games.