Golden Sun: Dark Dawn/WMG

Dark Dawn was made to mess with the shippers.

 * Face it: When the fanbase isn't making theories or sequel hoaxes, they're too occupied with shipping. So what better way to give the middle finger to the shippers than having a sequel that makes one pairing canon (Valeshipping) and none of the others specified? That's a way to mess with their heads.
 * It seems strange that Golden Sun has a large shipping fanbase to begin with, considering the series is basically a No Hugging No Kissing story that focuses instead on The Power of Friendship.
 * Are the characters shaped like humans and/or displaying of human emotion? Yes? Then there is a perplexingly large shipping fanbase.
 * Shipping occurs in all fandoms, even in series that in which they do not fit in at all (Resident Evil comes to mind).
 * But it does make every other possible pairing among the player character bogus (all 4 of the original characters have their own, apparently unreleated children) or confirmed (Jenna) except Felix and Sheba.

Amiti is Alex's son.
His mother died without telling anyone who his father was, his uncle has no clue, and he looks a hell of a lot like Alex.
 * Further credence to this theory: When you meet Tret, he reads the party members' auras upon hearing that they're the children of the Warriors of Vale, to see who they're related to. And when he reads Amiti's, he says that according to Amiti's aura, he's a relative of Mia's... The Sun Saga books explicitly refer to Alex as Mia's cousin, so it's entirely plausible that that's what caused the similar aura reading...
 * Even better; late in the game, when you're collecting the orbs for unlocking the Endless Wall, Arcanus/Alex has already paid Unan a visit to tell him that Matthew ought to be granted the Crimson Orb. One of Unan's ministers, if you talk to him, asks that if you're visiting him again, what happened to your mask? There's only one person in the party who could be mistaken for a maskless Arcanus...
 * I forget when it happens, but I belive it's when Kraden and Karis agree to not have Kraden tell everyone who Arcanus is under the mask, because they might wind up being close to someone in the group and make it difficult for them to fight against. During this conversation, Kraden is looking at Amiti.
 * On a smililar note, kudos for Karis for figuring out that Amiti is Arcanus' son, (possibly) before figuring out who he really is
 * Rief figured it out too. His reference to the implications of Alex being kin to one of them could have been referring to the fact that Alex is his own first cousin once removed, but given Rief knows what Alex did and seems to utterly despise him, it seems extremely unlikely he would be bothered by it.
 * Though knowing Alex, it's definite that he only does his actions to further his own goals. If he did know about Amiti's existence, he'd most likely use him as a pawn. (It is just as possible that Alex doesn't know anything about Amiti being his son or that he planned it all along.)
 * I am certain that someone as smart as Alex realizes that Amiti is his son (Amiti's mother, age, power, hair color, and even appearance fit according to some NPC). Even if he didn't know that he had a son, by the time Dark Dawn ends, he should have realized it. Even Kraden notices the connection. The question is whether Alex made Amiti on purpose, whether he cares about the kid, and whether he has more plans for the kid.
 * Also, Alex seems to be really interested in Alchemy Machines. He's been involved in the activating of almost all the major ones we activated in the game (and I'm pretty sure he was behind Chalis for the Alchemy Forge too). It really isn't too far of a stretch to say that he activated the Alchemy Well.
 * Apparently confirmed by a character tree posted by Camelot but I CANNOT FIND THE LINK.
 * Here http://twitpic.com/3foeq0.
 * The next question is, how many kinds of badly is Amiti going to take learning about it? He reacted badly to finding out he HAD a father...
 * Oh yes! Bring on the bishie angst!

The Umbra Clan/Tuaparang are descendents of the Anemos.
The city of the Anemos was indicated in TLA to have flown away and become Weyard's moon when Psynergy was sealed. They harvested all the light energy that could reach them to power their technology in the absence of Alchemy, which resulted in their continued technological superiority, and eventually in the mutation of their powers, since by using up all the light they left themselves in the dark.
 * Psynergy Vortexes may or may not be a weapon they are using to influence and shape the nations on Weyard's surface. This is suggested by the one in the caves under the Konpa Ruins, which appeared to be generated by a machine and was accompanied by Tuaparang soldiers.
 * When Alchemy re-emerged, they sent a team to investigate the greatest surge of it, the Golden Sun, which is where they found and recovered Alex after his scrape with the Wise One. Alex offered his expertise on present-day Weyard in repayment for his rescue, which had the handy-dandy side effects of granting him powerful allies and allowing him to continue searching for Alchemy Machines in his own quest. He activated the Alchemy Well in Ayuthay, and did some other stuff there as well.
 * Working with Alex, the Tuaparang orchestrated the activation of the Eclipse Tower, which siphoned light away from Weyard. They did this to power up a superweapon of their own, one whose effects will be seen in the sequel. They attempted to use the Apollo Lens to provide even more power (Alex asks them where they are aiming it in a cutscene), but our heroes prevented that by defeating them.

The Tuaparang are behind the Psynergy Vortexes.
While it may be the case that the Vortexes initially were natural phenomenon, the scene at the Konpa Ruins heavily suggests that the Tuaparang have machines that can create artificial Psynergy Vortexes at will. Perhaps this is related to their Darkness Psynergy and was an area of ongoing research for them. It is also suspicious that a few of the Psynergy Vortexes, the one in Carver's Camp and the one in Konpa Ruins in particular, were conveniently located to force the group to split up and eventually head to Ei-Jei. On a related note, psynergy vortexes were shown to shrink upon the defeat of nearby bosses. This will probably be incorporated into some puzzles in the next game. Similarly, a separate group of Tuaparang could have attacked Isaac & Garet/ Sol Sanctum during the events of the game & left behind that huge vortex as a warning...

Tuaparang will be a massive Cyberpunk metropolis, ala the city of Gestahl in Final Fantasy VI
It's already been shown that Tuaparang is ludicrously high tech with their massive military airship. Instead of having rusty brown buildings like the city of Gestahl however, Tuaparang would have a sleek black look to mirror the Luna Adepts who live there and solidify their Dark Is Evil motif.

Alex is going to try a Grand Theft Me on Amity
In fact, it's the only reason Amity was conceived in the first place. Amity inherited his psynergy, is next in line for the throne of his country, and has Insight, which Alex could never use. Since he knows that the Wise One screwed up his plan for ultimate power, might as well start again, and this time, making sure he's hiding as a hero.

The fourth game will star Felix's daughter
Why? Because Camelot realized there should be more variety to main characters than mute male Venus Squires. Also wouldn't put her being a Jupiter adept past them.
 * That's possible. Hacking Mind Read in Prox at the end of TLA also reveals that Felix is suddenly rather popular with the Fire Clan, so his Spin Offspring could really go either way. ... Or both...
 * Hell, two "full" siblings could be Mars and Jupiter. The game never makes clear how exactly inheritance of Adeptness works and Jenna is a Mars Adept.
 * It would make sense that Nowel was absent for a reason, She'll assemble her own Nakama for the sequel and likely take the place of Amiti, Sveta, Eoleo, and Himi when they meet up with Matthew and the others.
 * Takeru might finally put in an appearance as well.
 * Then that'll probably cover our Venus adept. So that just leaves us with whoever the creators make up for the Mars and Jupiter.
 * Done. This troper noticed on the character page that back in Lost Age, Kushinada said that Takeru would help the children of Felix's party if they were ever in danger, and also that Takeru had left before Dark Dawn because he sensed Isaac was in danger. So if they do decide to sink another ship rather than canonize it, they could actually have two characters as offspring of the Lost Age party--one child of Felix, who is for one reason or another a Mars Adept (as noted above, Felix is suddenly very popular with the Fire Clan, and besides Felix himself is obviously related to Mars Adepts), and one child of Sheba, who is a Jupiter Adept. Presumably the "second party" would be the returning main characters from Dark Dawn, although as we noted Rief was no longer with them when Matthew, Tyrell and Karis returned to Vale so we may still be one short.
 * After getting back to Vale and seeing the huge Psyenergy Vortex, they went back out and joined back up with him. Besides, for the ending of Dark Dawn to be about where that game's party comes in, the earlier part of the fourth game would have to be going on during the Grave Eclipse.
 * This troper consistently misreads your WMG as saying Feizhi's daughter will be the hero... hey, Camelot, let's see crack happen for the next game!
 * Quite possible, though I'd bank on Feizhi's child already having been in service.
 * I was about to say it seems profoundly unlikely that, but come to think of it,.
 * At any rate, Feizhi's absence from Dark Dawn's plot would be neatly explained by the war between Sana and Morgal; she sent her husband and their child back to his hometown while she stayed with her own people during the war. It never comes up when our heroes are in Sana because they're worried it would place stress on their friendship with Sveta and possibly Amiti (since Kaocho was a Sanan colony that broke away).

The fourth game will have an Evil Duo named Diamond and Club

 * We always have a Pink Girl Blue Boy pair of antagonists to string our heroes along, and who could bare to leave such a straight-forward motif half done?
 * But instead of the previous pink girl's pinker little sister, Diamond is going to be Spade's revenge-seeking EVEN MORE Badass BIG BRO.
 * Club will be an Agatio Expy and The Brute of the Huge Guy Tiny Girl duo with Diamond.
 * Blados and Chalis seem to match well enough to the Swords and Cups motifs described on our Tarot Motifs page. I'm guessing their successors would do the same. According to our article, the suit of Staves/Wands "deals with will, passion, and power. The Male symbol." So Club will probably be the guy of the duo and be Hot Blooded. The suit of Coins "deals with the physical, with wealth, health and growth" - I'm guessing Diamond is going to be a greedy girl. Oh, and I'll throw out a guess that their dub names will be Leangles and Galleos, respectively, borrowing from another series that used Blade and Chalice as tarot-themed names.
 * Alternately, Club will be an evil staff-using girl, and Diamond a dude. There, we've covered all our bases.
 * In the Japanese, Blados, Chalis, and Arcanus were Spade, Heart, and Ace. So they were card-based, but on a playing card deck instead of the Tarot. The next air will be Club/ Clover and Diamond in Japan, and then Coin/ Pentacle and Wand/ Staff in tthe US (though I can't remember how Club and Diamond match up to the Tarot suites...).
 * Club = stick weapon = Staff and Diamond = shiny and valuable = Coin.

== All the villains from Dark Dawn will ultimately turn out to have sympathetic motivations and/or be Well Intentioned Extremists... Except Alex ==

Because, hey, why mess with tradition?
 * Conversely: Alex will turn out to be a Well Intentioned Extremist opposing the will of The Wise One who turns out to be a Selfish Evil Jerkass God.
 * Most likely jossed. Alex crossed the Moral Event Horizon
 * And the Wise One
 * Alternatively, they're ALL Well Intentioned Extremist.
 * Entirely possible considering the plot twists of the first two games-- that everybody was trying to save the world, they just had different perspectives on how it was in danger.
 * Again, except Alex.

In the last game.

 * We'll have control of EVERY character from the games. Meaning we'll likely have a party totalling at about 20+ characters. Overkill? Maybe. Tottally kickass way to end the series and serve for one hell of an epic showdown? Damn skippy.
 * Maybe a tactical RPG like Shining Force? Made by the same company after all...
 * Hmm, it's possible. Though I would think Camelot isn't gonna shift too far from the traditional gameplay much. Though one would hope they'll at least spice it up for the 4th game since you can only make a solid game with the same mechanics so many times before it loses flavor.
 * Perhaps it'll be a split the party moment? except instead of splitting your party, you're splitting your party plus the other PCs. For example, you's have Isaac, Garet, Ivan, and Mia in one squad, Felix, Jenna, Sheba, and Piers in another, then Matthew, Tyrell, Karis, and Rief, then Sveta, Himi, Eoleo, and Amiti in another.
 * Possibly other squads including Takeru (Himi's brother), Nowell (Rief's sister), the other protagonists' kids, and/ or other awesome NPC's kids.

On Adepts in non-Adept communities...
After the seal of Alchemy, the Jenei and Exathi intermarried with the Fori, and their powers seeped into most bloodlines, so in theory, an Adept could come from any family or community. Most people just aren't strong enough to actually use or see Psynergy, because their Jenei blood is so dilute. As a result, we have mostly non-Adept communities like Contigo and Kibombo, where once in a while an Adept (Ahri or Akafubu) does happen, and people who are born non-Adepts before being exposed to elemental energies and developing new powers (Feizhi, werewolves, and Eoleo).
 * This also explains Feizhi's bright purple hair, and why Hama was trying to teach her Psynergy-- she could sense Feizhi's latent Adept qualities, and was trying to bring them out.
 * This also means Kraden could potentially become an Adept by the end of the series.
 * That'd be pretty epic if he were to be the big hero who saves everyone in the end in a Heroic Sacrifice.
 * And it explains why some NPCs in Dark Dawn (Briggs, Ikan, and Kaba) were able to see Psynergy, even though non-Adepts normally can't (the cutscene with the kids in Harapa).
 * Normal people have always been able to see the effects of Psynergy, just not the blue aura/huge hands/etc. Plus Weirdness Censor. The kids probably just saw the flame.
 * Which is why I cite Kaba, who specifically describes the aura, and Ikan, who mentions being able to see it as well.

Golden Sun 4 will take place during Dark Dawn.

 * Much like how Lost Age begun just a bit before the conclusion of Broken Seal (Golden Sun 1's subtitle), the next game will take place shortly after Nowell and Kraden were sperated from her brother and Matthew's group. It'll then follow them traveling to the places that Matthew and the gang would have passed through if not for broken bridge that prompted them to go all the way around (Carver's camp). Eventually, Nowell will meet Piers and as suggested above, Himi's brother, Takeru. Their journey will then take them on a mission that might possibly coincide with some of the events in Dark Dawn in subtle ways, eventually culminating in the story catching up just as Matthew and friends return to Goma plateu and witness the return of the Mourning Moon. Whether Camelot will then have the story continue from there or make us wait 'til a fifth game, I can't say...
 * Hm, I think I like the idea of Nowell being a PC, but I don't think they'd replay all those events, or at least have them go by quickly or something, so it doesn't end at the same spot chronologically.
 * End there? No. But I could see Matthew and friends' return to Goma Plateau being the equivalent of Jupiter Lighthouse, where the previous game's party joins the new party (which, like in Lost Age, was only four large until that point.)

Dark as an element is "Pluto" and light as an element is "Eris"
Well, little less set for light, but it would be one of the other dwarf planets.
 * Pluto being the Greek god of the Underworld makes sense for Dark, Eris being the goddess of anger/enmity/all that fun jazz, less so... then again the series is not above that.

Element!Light will be named Ceres

 * An amendment to my above, as I realized we have another roman god named dwarf planet. Stupid me for only looking at things after Neptune''. "agriculture, grain crops, fertility and motherly relationships" seems workable for light.
 * Probably jossed. The series' elements get their elemental affinities from Chinese Taoism's planetary associations. If either Light or Dark has an elemental name, it'll have to be Saturn to fit in with the theme. My guess is it'll be Darkness since I have a hunch that Light will be Sol or something sun-related.
 * That's not joshed that's just puttting it in doubt, also, Dark and Light are added afterwards and are equal, giving one a "full" planet as a name is unbalanced. Giveing both of them the names of Dwarf Planets fits their stats as new additions.
 * Bonus points for being the most importants dwarf planets. Ceres was the first dwarf planet to be found in the inner solar system (light) and it lead to the discovery of the rest of the asteroid belt. Pluto was the first dwarf planet to be found in the outer solar system (dark) and it led to the discovery of the rest of the Kuiper Belt. I'm expecting the developers to say Sure Why Not to this one.
 * Darkness Adepts are of the Umbra clan, which is Latin, so my vote is that light Adepts will be known as the Lumen clan. And since they started messing with light and dark only after messing with the elements, they might not have planet names. The closest I think you'd get is Sol for light Psynergy and Luna for dark Psynergy, with their clans known as Lumen and Umbra.
 * Or, you know, they could just be called Sol and Luna...

Imil and Lalivero are protected from the Grave Eclipse thanks to the lighthouse's... light
Will have to check, but I think you could see the Mercury Lighthouse is the Eclipse, and it was dark.
 * No need for that with Lalivero, it's far south of the Eclipse. Imil is in the danger zone though, yes. Possibly the area round Mt Aleph too, that's roughly where the western edge of the eclipse should be.

GS 4 will revisit the lighthouses
A little remembered bit of TLA's ending is that the area around the lighthouse will be dangerous thanks to Alchemy's release, but nothing is expanded on. I doubt it will be to shut them off, perhaps to keep someone from using them somehow?
 * Possibly alluded to in the very beginning of Dark Dawn, when Tyrell mentions the older Adepts must have wanted the Soarwing to retrace the steps of their own journey.
 * In the beginning, Isaac does explicitly say that he and Kraden believe that the Psynergy Vortexes were somehow caused by the lighthouse beacons. This is almost a certainty.

Arcanus is the real leader of Tuaparang
The High Empyror is at best a political puppet on a standard "Take Over the World" power trip whom is manipulating. Blados and Chalis realised this, and that's why
 * That's a damn good theory! Blados realises that and up until the Apollo Sanctum Blados, as evil has he had been, still followed the orders he was given. Him and Chalis  at the Apollo Sanctum was the only sign of true  that we've seen from either of them.

Isaac's "danger" is from Alex, who needs to achieve the 6th and final element, Mars
At the end of TLA, Alex doesn't get the ultimate power from the Golden Sun because The Wise One did something to the Mars Star. The only remotely reasonable motivation for Alex activating the Eclipse, then helping to stop it, as far as I can see is to gain Light and Dark powers, on top of the Venus and Jupiter he gained from the Golden Sun. Now Alex will use the Light/Dark powers or something to gain the missing part from Isaac and become a god.

Matthew has a sister.
They never said he was an only child. We only assume so because Matthew was the only one with his Father, but if Isaac and Jenna had more than one kid the other one(s) could be with Mom. If this is true, then she's probably a Fire Adept.
 * If there's a sibling for anyone, they'd be pretty young to not be up at the cabin training with Isaac and Garet.
 * Or, possibly, they're older siblings, and have already grown up and left the nest.

And if the above WMG about the next game following Felix's daughter is also true than maybe the initial party will be gender inverse to the one from Dark Dawn. Female Venus Adept (party leader), Female Mars Adept, Male Jupiter Adept, and Nowell.
 * And that sister will turn out to have inherited the portion of the Mars Star that was given to her father because she inherited her mother's element. That's why Isaac and Jenna aren't shown together. Their daughter needs to be kept out of plain sight so certain people don't go after her. Jenna is also making sure her daughter's enhanced Mars psynergy is properly trained. The game's plot will heavily involve keeping the enemies from getting their hands on her.
 * As for the next game's initial party, it seems more likely that the initial Mercury adept will be a child of Piers and a warrior to boot. Nowell will be the party's second Mercury adept like Amiti.
 * There is zero evidence that Isaac has any idea that he has a piece of the Golden Sun in him.
 * Not based on what we know now, but if he had a child who's power over Fire surpasses even his/her Golden Sun empowered mother, they would probably start suspecting something.

The next game will increase party size...
...So that you can cover all four base elements and add in a Dark/Light adept as well.
 * That or people can have dual element classes with a standard element plus light or dark. Ooooh, what if they have light/ dark Djinn?
 * How about playable non-Adepts? We're told that Psynergy Vortexes mainly affect Adepts, and if the other theories about going to explore Sol Sanctum, the Lighthouses, and/or the Mourning Moon are correct, having allies who aren't as affected by Vortexes could be handy...

Matthew and Sveta are now Light Adepts
as signified by their glowing golden (or in Sveta's case, just glowing) eyes in the stinger. As the first two games explained, normal people can become Adepts through prolonged exposure to Psynergy directly (The Valeans and Mt. Aleph) or indirectly (Strong winds from Air's Rock carrying bits of Psy stones through Garoh), or with a large or concentrated amount in a short time (like Feizhi and the Psy stone that hit her head). When Matt and Sveta were exposed to large amounts of Light-based Psynergy from the Apollo Lens, but the exposure would have killed them if Volechek hadn't literally stepped in; as such, Matthew is now a Venus/Sol combo, and Sveta is a Sol/Jupiter combo.
 * I have to wonder how that works... true, Matthew's spirit was in Sveta in the endgame, but not his body. (That Came Out Wrong) It is plausible that psynergy is transmitted by spirit as opposed to body, but we can't be sure until they return. Also, there is the Umbra Gear to consider: creating a shield of darkness as protection from radiation. Plus, there is little doubt that Alex may have powers that require somebody to invoke Dark Is Not Evil . So, Matt likely would be Venus/Sol, but I'd expect Sveta to be Jupiter/Luna.
 * Agreed. Considering the theme of balance in the series, it would make more sense for one to be light and the other dark. Plus they have the male/ female dichotomety going, plus the fact that the beastmen are already closely tied to the moon, which sees to be connected to darkness.
 * The Moon also has a pre-existing connection to the Wind element, being implied to be the location of the ancient world's Jupiter Clan. There's also the connection from real-world astronomy in the way the Moon's gravity affects wind-patterns and tides. The description of the elements after the reunion in Contigo would also imply that Earth and Fire have the stronger connection to the Sun given their characterization as "warm" elements.
 * Holy crap, you are amazing for making this connection. More foreshadowing of Light/Dark from the first two games?

Blados and Chalis are...
The reincarnations of Saturos and Menardi, respectively, as Tuaparang. However, they retained their memories of their past lives (save Alex, because he would have had something in place to make sure they forgot about his true the front he projected to be his true nature), and realized that the Tuaparang were utter dicks compared to the Proxians, and decided to do the world a favor, repent, and wipe those bastards off the map.

The Descendents will join the main group in the fourth game...
...but not the Regents. Sveta and Eoleo have to rebuild their respective nations and Amiti's uncle may still be on death's door. Only Himi would be available to travel, and most speculation is that her brother Takeru would be part of Game 4's main party. Never fear, though; there will come a time later on when all of Gen II will combine for the Final Battle against the Tuparang/Alex. (But not before a Fire and a Water adept also become dual-types per a previous WMG, should Matt & Sveta also be dual-typed.)
 * Would be really interesting to see whether Fire goes Light or Dark in that sense. Fire produces light, so that would seem obvious, but Fire Adepts have generally been a pain in the ass in the storyline, if not outright antagonistic (Fire Clan, Champa, Kibombo, Tyrell...).

A Proxian will be part of the team in the 4th game...
...and basically be a Fire version of Sveta. Complete with the ability to shapeshift into a Dragon.
 * Except that Dragon Mode seems to pretty much be a Fire Clansman's "swan song", whereas werewolves have been established as able to survive and control the transformation.

Amiti was born to hold the power of the Mercury star.
We've already established that Alex is Amiti's father, and it's also known that Alex has most of the Golden Sun absorbed. It's possible that Amiti got the power of the Mercury star and it's residing in his body so that it won't fall into the wrong hands. Though alternatively (and more likely), Alex was storing it in Amiti to save it for later and when he wants the power back, he'll try to kill his own kid, possibly using the Luke I Am Your Father revelation to stun him. And if this were true, it's likely Alex would have fathered other children to act as human vessels for the Jupiter and Venus stars.
 * Canon or not, do you mind if I steal that for my fic?
 * Go ahead. Besides, this page is for everyone's guessing.
 * In that case, would that mean he has bastard children that are Jupiter and Mars Adepts floating around too? Preferably either in a position of power (like Amiti as a prince), responsibility (guarding something he needs), or where they can learn a valuable skill (special Psynergy, a trade like smithing, tactics, etc.)
 * Jupiter and Venus spawn. Alex is Mars-challenged.

Darkness and Light Psynergies were planned for as early as the first game
Though guesswork that may never be confirmed or denied, it seems likely that Sol Sanctum with its depictions of both Sol and Luna may have been an extremely subtle hint that there were more elements than just the classical Earth, Wind, Fire, & Water.
 * True. I need to see Kraden's comments on the sun and moon rooms again, he was curious as hell about it and we never got any answers. I *think* he was curious as to why the moon was featured along with the sun in the Sol Sanctum.
 * The mechanics of Cloak Psynergy involve using darkness and shadows to hide yourself and your friends. Holy crap. They not only planned for this stuff, they gave it to us as a spell already.
 * Of course, Cloak also counts as Water, so unless they change it like they did Move, this just raises more questions about how exactly Light and Dark relate to the other elements.
 * Possibly Cloak was counted as Water because nobody knew about Dark Psynergy yet, justifying the reclassification in-verse?
 * You'd think the user would notice that s/he was drawing on something other than the four classical elements.

One of the first missions Golden Sun 4 will involve going to the remains of the Sol Sanctum
And either re-exploring the sun and moon rooms mentioned above, and/ or discovering additional chambers related to light and darkness psynergy. This could possibly be used to show off Matthew's newly acquired Light Psynergy, if he got some as speculated above.
 * The ENTIRE POINT of heading out on this quest was to fix the soarwing Tyrell broke so your family could study the remains of Sol Sanctum and Mount Aleph. So once you deal with The Stinger, it's time to go Indy all over that mountain. Heck, you might need to do so in order to deal with The Stinger at all.

Kraden is now a Light or Dark Adept
And may have been one for a while. Keeping hush on Arcanus makes me think of him as a bit of a Magnificent Bastard, even if it wasn't that big a deal. He has the potential, I think. Remember how he got a couple of kids to break into a sacred, forbidden shrine?
 * Or coaxing the group into randomly finding Susa in Dark Dawn, apparently on a hunch that Susa would have some way to help them, but insisting he didn't know whether Susa was still alive. In front of a pirate who repeatedly brags about how well he knows the Eastern Sea and who would surely know what happened to Izumo and its people.

The effect of the Golden Sun making the main characters age slower is only a cheap plug by Camelot to have Kraden in the game - for now at least
Think about it. From the nine main characters in the first two games (counting Kraden for that as well), you only get to see three, two of them only at the beginning of the game (and they don't even need that slower aging effect to live after 30 years) and Kraden's portrait looks exactly like the one in the originals. And before you say "But he was 70 already", well, it only slows down the process of aging, it doesn't stop it.

Alex killed and impersonated Piers

 * Both have blue hair and use Water Psynergy, and he can Teleport Spam, appearing to be in two places at once, and wears a mask (which he removes when masquerading as Piers).
 * This is how he convinced various NPCs to help the party out, as it advances his own goals.
 * As Piers, he seduced and impregnated Amiri's mother.
 * In a Squickier consequence, it's Alex that Nowell is actually infatuated with, which he will use to turn her against the heroes at some point in the future.

Blados is G La DOS, or more accurately a construct of her.
Based on the names, and the fact that he manipulates you into going through a puzzle that turns out to be a trap.

Piers is the Star Magician

 * Following the above WMG, Piers was murdered by Alex out at sea, and the Lost Ship is his. Demanding vengeance, various spirits/Dark Psynergy turned him into the Star Magician.
 * But, Star Magician was in Lost Age.
 * Yes, but he was killed by them, and is one of the sprirts that took over Pier's corpse.
 * Wasn't the Lost Ship said to belong to someone in game? (I'd have to go back and see who)
 * There's one room on the Lost Ship where the captain's corpse can actually be found, and I'm sure Kraden would have said something if it was Piers's, or that the corpse itself would mention this when you Spirit Sense it. I'm gonna call this one Jossed.

Goats are Stealth Experts in the Golden Sun universe

 * As the tablets tell you themselves: THE GOAT LEAVES NO TRACE BEHIND.

Incoming world-wide disaster after the Grave Eclipse.
Basically, the Eclipse messed so much with the climate that we were seeing ice floes in strange places even in canon-- care to imagine what that would have done to plant life, including crops? And with so many plants dying, to the wildlife? Food's about to run desperately short for the Eclipse survivors on Angara, causing even more wars to break out over what few resources are left. Mainland countries would start attacking areas that weren't affected as much by the Eclipse for their resources. And of course, being a nation built on war, the Tuaparang stand to benefit more than anybody else from world-wide conflict...
 * Most likely, we'll see the return of the "Mourning Moon" that was constantly mentioned at the beginning of the game, but like everything Psynergy Vortex related, disappeared very quickly.
 * ... until the stinger.

Takeru, Himi's Brother well be the Next Protagonist.

 * Why? Well would you think that Felix would have a Son? Beside seeing that Himi is a Venus Adept herself, Why not him.

Each Tuaparang has an Akatsuki(Naruto) counterpart.

 * Blados: a Blood Knight with a BFS, a Meaningful Name and Anime Hair that sticks straight up?  Arcanus: a Magnificent Bastard Big Bad who manipulates the other members, has a Secret Identity, is older than he looks and  ?   Chalis: she doesn't seem to have a counterpart, but this troper likes to think that this is who Konan would have become if she wasn't a Satellite Character...

Blados is related to the (first) Dullahan somehow

 * Just look at his armor.

The next PCs will be... (feel free to add)

 * Nowell
 * Takeru
 * That one beastman kid who has Light Psynergy.
 * Ahri - remember her? The little baby in Contigo that would cast whirlwind in the middle of her home. Yeah, she'll be one of your Jupiter adepts in the next game.
 * Playable Christmas Cake? Yes, please.
 * ... Christmas Cake? At thirty? Now Hama on the other hand...
 * Threshold for Christmas Cake is twenty-five. Thirtyish qualifies. Hama, on the other hand, is Ivan's older sister, and Ivan's almost fifty as of Dark Dawn era, so Hama would be a whole other set of tropes.

In the sequel...

 * Judgement and Catastrophe will become summons for Light and Dark Psynergy respectively.
 * Probably not. Judgement is pretty much the definitive Venus summon and Catastrophe still uses a LOT of lightning. If any summons become Light or Dark aligned, it will be Iris and Charon.

Weyard is becoming Earth

 * Think about it: In the first two games, Weyard looked vaguely like Earth if you had a good enough imagination, but Dark Dawn more or less proves Weyard is becoming Earth. You're mostly in Asia, (Sana is China, Endless Wall=Great Wall of China, there's even a Japan equivalent!) All of the locations and even cultures are oddly similar to Earth's, don't you think?
 * This troper thought it was curious that Weyard has gone from being more or less a flat Floating Continent to being a little more three-dimensional in Dark Dawn, with impassible drop-offs and ledges in the ocean where before the only "drop-off" had been the literal edge of the world at Gaia Falls. If it's developing into a spherical planet as a result of the Golden Sun Event, that might explain some of the massive geological upheavals, and possibly even some of the Psynergy Vortexes-- energy being redirected from areas where it's concentrated (Adepts) to areas where it's needed, much like windstorms in real life are air under high pressure moving to areas of air under low pressure.

Vande the wolfman will play a major role in the next game.
Only one of the Belinsk band members to have a name, and a character portrait when he speaks? Definitely signs of importance here, but he had relatively little plot significance (he wanted to see the Mountain Roc, which you were going after anyway). Plus, he gets a whole new character portrait at the end of the game,. Either he's the remains of some cut content, or he's something important that's yet to happen (the changed portrait suggests the latter).
 * Bullet points for this theory go here.

Tangentially...

Vande the wolfman is from Garoh.
He's the correct type of beastman (wolf), and he seems enthusiastic about everything he sees, as if he weren't from around here...

Sveta and Volechek are the children of a wolf-person and a deer-person, explaining why their animal traits don't really fit with any single type of animal as with other beastmen-- they're hybrids.
Neatly explains what happens when two beastmen not of the same animal type marry, explains why Sveta's nickname is "the White Deer" when her beast form is clearly a wolf, etc. Her ears could pass for stlyized deer ears, and her muzzle and claws are so slight that they could come from anything. Volechek's features are more blatantly animal, but also seem to be a blend of cervine and canine features.
 * Also, Sveta describes her father developing a hatred of humans after living surrounded by their hate and Fantastic Racism, which is also very reminiscent of Garoh (compare Maha's more philosophical discussion of the topic in The Lost Age).

Tuaparang is Actual alligned to the element of light, not Dark.
It's just what is said in the conversation between Arcanus with Blados and Chalis in Apollo Sanctum. From the sounds of it the High Empyror should not know Blados and Chalis are dark adepts. There is also the fact Tuaparang is referred to as Zenith Tribe, Zenith being another word for Midday ,I think. It would make sense why Tuaparang activated the Grave Eclipse, they want to create an army of Light Adepts, so either torture or mind control will be unleashed upon Morgal's population.

Felix is the High Empyror.
Felix is mention to have vanished and never seen again, and no one knows what the High Empyror looks like beyond Tuaparang. Also when Arcanus talks to Blados and Chalis he is talking to them like traitors and that they might aim the Apollo Lens at Sol Sanctum as some sort of super-weapon, so they might be attempting to get on Felix by obliterating the place where he started his quest that caused his immortality, which would be more likely is Felix is the High Empyror and Blados and Chalis want to get a one up on him as a part of a possible treachery.

Alex left Apollo Sanctum entirely, for reasons that fit his M.O.
Just before the final fights, Alex "holds off" Blados and Chalis, and all three of them zip offscreen. Then Blados and Chalis return, and Alex's only other interaction is to telepathically(?) warn Matthew to stop trying to get on the Apollo Lens's firing platform. Why would he just leave? Simple. The same reason he left the Mars Lighthouse in The Lost Age. He had somewhere to be, and something to steal. In other words, he was trying to pull a Mount Aleph. In Dark Dawn, Alex knew that in a few minutes, the Lens was going to saturate the Eclipse Tower with enough Light energy to end the Eclipse and release all the light in a big burst around Belinsk. This burst bestowed all the human Beastmen with Light Adept properties, and Alex wanted in. In other words, he pulled the same trick. I'll bet he flew right into the center of the Eclipse so that he could absorb as much of the Light power as he possibly could. Just to power himself up some more.

If Matthew appears in GS 4...
Given that Isaac was silent in GS 1, and suddenly started talking in GS 2, everyone's expecting Matthew, who was silent in GS 3, to talk if he appears on GS 4. Sound logic, yes? But then Camelot, suspecting this, keeps Matthew silent in GS 4, save for his "?!" talk... Perhaps they would make the new protagonist more talkative to compensate.

The fourth game will have elements of Light Is Not Good
To contrast the Dark Is Evil of DD.
 * Not invalidating this WMG, but the Umbra Gear begs to differ the evilness of dark in DD. Golden Sun Grey and Grey Morality get.

Ryu Kou is an Adept.
Bear with me here:
 * @ Te Rya: Hou Zan asks if Matthew and his friends are Adepts. Ryu Kou immediately chucks a hissy and complains that they shouldn't be talking about such things with suspicious strangers. Why so jumpy about Adepts, unless he has something to hide?
 * @ Mountain Roc: Taking the Slap Glove. They knew Sveta was an ally to Matthew, so he would have access to Slap anyway, whether he had the Glove or not, making taking it from him pointless... unless they were able to use it.
 * Counterpoint: The point of the Slap Glove is that Anyone can use Slap with it. Being an Adept may not be a factor.
 * @ Belinsk Ruins (1): They get in through an alternate entrance. The only other entrances we see are the one from Belinsk Castle (the one Sveta took; since that's their destination it can't be the one they took) and a Slap statue.
 * Obviously that's why they took the Slap Glove back from Matthew in the first place. The question becomes when did they find out about that route, and that only one fire shard was needed to open it the rest of the way.
 * @ Belinsk Ruins (2): En route to Luna Core, a guardian system states that everything's supposed to be handled by Adepts, using Psynergy. Ryu Kou's reply, if I remember correctly (I might be incorrect), is more along the lines of "I'll leave this to you" than "I can't use Psynergy".
 * At which point, Tyrell calls him out for not pulling his weight. Even taking into account that Tyrell is a bit boneheaded, previous cutscenes have established that he does know non-Adepts can't use Psynergy and wouldn't be able to solve the puzzles, so he shouldn't be complaining... unless he knows someone is more capable than they're letting on.
 * @ Luna Core: Per Arcanus's demands, Ryu Kou activates the machine everybody's telling him not to activate... which is also supposed to be Adepts-only. Possibly hand-waved since Matthew & Co. did do most of the heavy lifting already, but wouldn't the guardian system comment on that?

In conclusion, it does seem to me that Ryu Kou is an Adept, possibly only a very weak one, hiding his powers out of distrust for the others or possibly fear of his powers being overestimated or used against him.

What element? Hard to say.
 * He could be a Fire Adept. He's got the temper, and he's already been set up as something of a foil to Tyrell in their arguments.
 * He could be an Earth Adept. He's got the whole "misguided heroics" thing going on in opposition to Matthew.
 * He could (I'm stretching here) be a Wind Adept opposite Sveta, just to demonstrate that Sana and Morgal are Not So Different.

Or, alternately, he has some kind of undefined power ala Feizhi.
 * Er. Feizhi was identified as Jupiter by Hama in the first game, wasn't she?
 * Not exactly. Precognition was defined as a Jupiter power, but Feizhi's element wasn't. All things considered, it probably is Jupiter, but that's another story. In any case, what I was getting at is that we know that there are some adepts who don't have much power, such as Amiti's uncle, and are hardly considered to be true adepts because of it. She may qualify as one given that we never actually see her use any real Jupiter power. Similarly, Ryu Kou may have some psynergy but not enough to qualify as a "full element" adept.
 * Worth noting that Himi and the late Lady Uzume are/were Venus precognitives, so Hama was mistaken about that.
 * Incidentally, King Paithos mentions moving rocks with his powers, so he's probably Venus, too (I think about these things too much). Unless they don't retcon/replace Lift and leave it as a Mercury power.
 * However, Hama is specifically shown training Feizhi's power, which she probably wouldn't be able to if Feizhi's power didn't correlate with her own-- and Feizhi's hair fits Jupiter's color scheme way too well.
 * That and Feizhi has purple hair, which is considered the definitive Jupiter color.

Amiti’s mother didn’t die in childbirth
Rather, Alex killed her. Think about it: Now that he has his son, a future pawn in his nebulous grand scheme, Veriti is more of a liability to him than anything else. It’s implied that she knows who he actually is, and as his plot seems to rely on anonymity (albeit with 1/3 of a mask, and a flimsy alias), it would be far easier for him to simply kill her rather than leaving her alive and risk her revealing his secret. Alex has shown time and time again (as well as outright stated) that he has no trouble discarding those who are no longer useful to him. A former lover from a one sided relationship should have been a piece of cake.

Babi is the High Empyror
As we saw in GS 1, Babi know how to use Cloak, a Psynergy that allows the user to turn invisible while in a shadowy area. Knowing that he was about to die, Babi decided to exhale his last breath with Cloak activated (probably to not be remembered as a sufferer by his subjects). Because of his last act, his soul did not go to the world after death as he thought: in fact, his soul and mind was sent to an alternative dimension where the dark and the shadows are the only source of light. There, Babi discovered the existence of the Dark Psynergy and used it to create and be the leader of a new life form, better known as the Umbra Clan (since Umbra is the Latin word for "shadow").

Alex is the source of the Vortexes
Alex makes the Psynergy vortexes for the purpose of hoping to get the Mars Star power that he lacks. If this is true, he'll probably use it in the future.
 * Maybe not even in the future...