I know people have picked up on the board game scene in RWBY V2 Episode 2 (Welcome to Beacon) as foreshadowing the events of the show, but for funsies I want to take a stab at how it foreshadows the general arcs of each four kingdoms myself.
So we have Blake playing as the Kingdom of Vale, and she's completely unaware of the events of the game unfolding and not really paying attention, clearly distracted.
"Alright Blake, it's your turn!"
"Huh? Sorry, what am I doing?"
"You're playing as Vale, trying to conquer the four kingdoms of Remnant!"
The Vale arc is the first three volumes of RWBY, where all our protagonists are at Beacon, but during that time, much like Blake during the game, they're unaware of the larger conflict with Salem, and aren't actively participating in the war at that point. They are ignorant and reactive instead of active. However it's ironic that Blake plays as Vale, since the reason she's not paying attention to the game and seems distracted is because, out of all the main characters in the Vale arc, she is the one most concerned about being kept in the dark and that they're ignorant as to what's really going on.
Blake: I just, I don't understand how everyone can be so calm.
Ruby: (approaching Blake) You're still thinking about Torchwick?
Blake: Torchwick, the White Fang, all of it! Something big is happening and no one is doing anything about it!
She also leaves the game during her turn, much like how she runs away after the FoB and the end of the Vale arc.
"Right. Well, I think I'm done playing, actually"
Yang is playing as Mistral, and she's the most savvy and knowledgeable (hah) player, winning many rounds of the game, teaching Weiss how to play, and has the other players falling into her trap cards.
"Heh, pretty sneaky sis, but you just activated my trap card!"
There's two ways this can be interpreted, with how the Mistral arc (volumes 4-6) is when our protagonists start to gather more knowledge and awarenesses of themselves and the world. It's also in Mistral that our heroes have their most decisive victory so far. It's fitting to have Yang playing as Mistral then, since during the Mistral arc she's the one who who learns from Tai to fight smarter, and to question the authority figures around her from Raven, and after confronting her in the vault is the one who retrives the relic of knowledge.
But, most of the losses our heroes experience are because of Cinder, who is from Mistral, and them falling into her own "trap cards" with the Fall of Beacon being orchestrated by her, killing Pyrrha and Ozpin. And in Atlas the same, with her manipulating Ironwood, undermining the heroes plans to evacuate everyone from Atlas, and killing Penny. She often finds ways to trick and exploit others, and is most dangerous when overlooked and underestimated, like falling into a trap.
Which brings me to Ruby playing as Atlas, where Ruby and Yang have this exchange after Yang's trap card is activated by Ruby:
"Giant Nevermore! If I roll a seven or higher, fatal feathers will slice your fleet in two!
"But! If you roll lower a six or lower, the Nevermore will turn on your own forces!"
"That's just a chance I'm willing to take"
In the Atlas arc (volumes 7-9) the theme of trust and taking risks is very prevalent. Like the move Yang makes in the game it is a risky one, that could end badly for her, but it is one worth taking nonetheless. They take the risk of trusting Ironwood but he ends up turning on our heroes. Oscar takes a risk trusting Hazel and Ozpin, as well as Emerald later on being accepted into their group, and it ends up working out for them. Ruby takes a risky chance in sending a message out to all of Remnant and evacuating Atlas, which saves a lot of people, but they still lose some, including Penny, a dear friend of Ruby's.
"Noooooo! My fearless soldiers!"
"Eh, most of them were probably androids anyways"
"Goodbye my friends... you will be avenged!"
Ruby acts distraught when losing her turn in the game as Atlas, expressing anguish over losing her friends who are described as androids by Yang, just like how Ruby is incredibly depressed and broken after the Fall of Atlas in V9, mourning the loss of Penny, who was both a sentient android and Ruby's friend. (I do wonder if Ruby's comment on avenging her friends might be foreshadowing for her wanting to avenge Penny's death in the future, like how Jaune tried to 1v1 Cinder in V5 to avenge Pyrrha, but I think it's too soon to say)
As a sidenote the fact it is a Nevemore in this turn that has a chance of turning on Yang or helping her is interesting, as it puts me in mind of two characters who can turn into ravens/crows, like the bird and poem Nevermore is associated with. It could pertain to Raven, someone who turns on Yang in v5 during the battle of Haven, but appears to help her and her friends in the V9 epilogue. It could also be about Qrow and his semblance, since during the Atlas arc it begins to evolve so that it is not simply a bad luck semblance, but one that can generate good luck too. In other words he can affect whether the chances are in people's favour or not.
After defeating Ruby (Atlas) Yang says this:
Yang: Not until I draw my rewards! Which are double this round thanks to the Mistral Trade Route!
Yang: Oh, and what's this? The Smugglers of Wind Path?
Yang: I say, it looks like I'm taking two cards in my hand!
After the Fall of Atlas Cinder retrives not one but two relics for Salem, and with Atlas falling into Mantle, two kingdoms are destroyed in one fell swoop.
Then it's Weiss's turn. Weiss is playing as Vacuo, but has no idea how to play the game. Yang takes it upon herself to teach Weiss how to play and what she can do to win the game:
Yang: Well, Weiss, it's your turn.
Weiss: I have... absolutely no idea what's going on.
Yang: (Yang slides up beside her and puts her hand on her shoulder.) Look, it's easy! You're playing as Vacuo which means that all Vacuo-based cards come with a bonus.
Yang: See, you've got Sandstorm, Desert Scavenge... Oh, oh! (She pulls up a card to show Weiss.) Resourceful Raider! See, now you can take Ruby's discarded Air Fleet—
Yang: —and put it in your hand!
We know from the end of V9 that what remains of the airfleet of Atlas, as well as the airfleet of Mistral and Vale, have all flocked to Vacuo's defence. What remains of the kingdom of Atlas, the airfleet, but most importantly the people, have now fled to Vacuo and are trying to make a home there.
Yang continues to give Weiss advice on how to win the game to Weiss, building her up, until Weiss starts to get arrogant, believing she's going to win the whole game and is the one in control:
Yang: And since Vacuo warriors have an endurance against Natural-based hazards, you can use Sandstorm to disable my ground forces and simultaneously infiltrate my kingdom! (Yang points a finger at Weiss.) Just know that I will not forget this declaration of war.
Ruby: You're just three moves away from conquering Remnant!
But then Yang turns on Weiss, activating her trap card, and Vacuo loses.
Since this is may be foreshadowing for the Vacuo arc that we haven't seen yet, I can only speculate what this might mean.
...But judging from the V9 extended epilogue and the books, my best guess would be that if Yang/Mistral is meant to be in part Cinder/Salem and their forces, then Weiss as Vacuo is in part the Crown. In the extended epilogue Jax and Gillian appear to be recieving help from Tyrian and Mercury, meaning Salem has decided to recruit them to her cause.
The Crown wants to restore the Vacuoan monarchy and detest outsiders, especially Atlesians. They do however wish to protect Vacuo from the same forces that destroyed Beacon, aka Salem, and so they are likely going to be manipulated like Weiss is by Yang in the game, being offered aid and giving them advice on how they can win and achieve their objectives, making them believe they can "conquer Remnant", only for them to realise later they were being tricked and used.
"Once again, Vacuo had been isolated from the conflict raging throughout Remnant—only this time it was an opportunity. With the global CCT network disabled, Vale in ruin, Haven leaderless, and Atlas closed off, Vacuo was theirs for the taking. This was likely their last, best chance for a generation. And it was their only hope to defend Vacuo against whomever had been targeting the other kingdoms. In likelihood they had written off Vacuo, like everyone else did, but if they tried to move against the Crown, they would have an unpleasant surprise.
Vacuo wouldn't break this time around."
Weiss: (Weiss stands and a thunder clap accompanies Weiss' overjoyed psychotic laughter.) Y-yes! Fear the almighty power of my forces! Cower as they pillage your homes and weep as they take your children from your very arms!
Yang: Trap card... (Yang's arm appears holding the card.)
Yang: (Yang shuffles the pieces on the board, Weiss' pieces disappearing in a puff of smoke.) Your armies have been destroyed.
Weiss: (Weiss slumps in her chair, cries and whines.) I hate this game of emotions we play!
Weiss as Vacuo may lose to Yang after realising they've been tricked, but is offered comfort afterwards by Ruby who relates to her losses and empathises with her, which is interesting since Ruby plays as Atlas. So I'm predicting at the end of the Vacuo arc they'll experience somewhat of a loss, whether that's the Crown, our heroes, or likely both, but Atlas will give support to Vacuo and the two kingdoms will come together to heal and ultimately work together, making steps to overcome their tense history with one another.
"Stay strong Weiss we'll make it through this together!"
"Shut up, don't touch me! "
...Which does make Weiss specifically playing as Vacuo especially intriguing, as she is the SDC heiress from Atlas, and Vacuo is a kingdom that has suffered the most in being exploited and colonized for it's natural resources by Atlas. From the epilogue it seems like the Schnees are being confronted directly with all the harm that has been caused by their family and kingdom, so I wouldn't be surprised if Weiss recieves a certain amount of focus during the Vacuo arc in deciding what her legacy as an Atlesian and heiress to the Schnee name will be. Moving forward to make amends, maybe inspiring the citizens of Atlas/Mantle to come together with Vacuo so they can all help and support one another, instead of isolating themselves and suffering alone.
Jaune offers to plays Weiss's hand for a turn also, with Weiss refusing:
Jaune: (Begging with both hands folded together.) Come on, let me play your hand for a turn!
Weiss: I'm not trusting you with the good citizens of Vacuo!
Which is reminiscent of how Vacuo is mistrustful of outsiders, as we've seen in After the Fall and Before the Dawn books.
Yang follows up to say that Weiss attacked her own forces, which could reference the infighting in Vacuo, especially with the Crown.
Weiss: Besides, this game requires a certain level of tactical cunning that I seriously doubt that you possess.
Yang: Uhh, you attacked your own naval fleet two turns ago. (Weiss makes an annoyed sound.)
Overall Weiss as Vacuo recieves the most help as any player during their turn, being taught how to play by Yang, offered comfort by Ruby after losing, and Jaune wanting to help her by playing her hand for a turn. This seems to fit with both how all kingdoms have flocked to Vacuo's aid in response to Ruby's message, but also Weiss as a character, who starts out "the loneliest of them all" but gradually opens up and warms up to other people. The crux of her arc being looking outside herself and at the people around her, relating to their struggles and coming to support them and being supported by them leads to her better understanding herself and becoming stronger for it... Which is kind of what the Kingdom of Vacuo needs to learn too!
Following this is Blake's turn as Vale, which I covered at the start of this post, but that's not the end of Vale's turn. We don't actually see it, but we know the aftermath of the game is this:
Yang: Ugh, we should have never let him play!
Ruby: You're just mad cuz' the new guy beat you!
Blake leaves the game during her turn as Vale, and presumably the "new guy" which is likely Neptune, who they'd just been introduced too, takes over her hand as Vale and wins the game of Remnant overall, even beating Yang and her trap cards. This is likely the endgame of RWBY itself, our heroes return to Vale after the Vacuo arc during the last volume for the final stand, where they win.
How and what that victory will look like I don't know, as we don't see the last turn of the game, so yet again this is even more vaguer speculation. Neptune doesn't really have much plot significance so I can't think there's any meaning to that except that he's a minor foil to Jaune, and the line of it being "a new guy" that wins, so maybe someone who recently joins our heroes side in the final act of the story, possibly Mercury or Cinder.
