More Discord ramblings...

One thing I've come to appreciate about Cythera is just how quickly the character is thrown into the deep end, plot-wise
You're summoned to Cythera by Alaric, and you think you're in for a standard isekai fantasy "save the king, save the kingdom" plot
Then, almost as soon as you actually get control of your character, Omen appears and makes it clear that there's a lot more going on behind the scenes
And by the first town you visit, you're introduced to the political intrigue between the Houses

Lately I've been thinking about the hypothetical Cythera 2 (as you do)
In Cythera 1, the objective is laid out for the player plainly from the outset: Alaric has summoned the player to Cythera, and they must cure the LandKing so he has the power to send the player back home.
How this is supposed to be accomplished is not immediately made clear, but the player is very quickly introduced to two complications that are important to the endgame: Cythera's House Politics (Comana vs Everyone Else) and the Elemental Conflict (Seldane vs Undine, the Crolna).
In the hypothetical sequel, the player returns to Cythera by unknown means, and Alaric is apparently very dead.
It is not clear if the main goal is to revive Alaric (if that is even possible), or something else entirely.
However, the Third Prophecy of Neleneus the Savant gives some insight as to what the possible complications might be:
"The World shall be sundered before the Coming of the Dawn.
And shattered shall it be ever after."
Island be broken, yo. It's not clear what the fault lines are, but we can guess that it's not an easy walk from LandKing Hall to Land's End Volcano anymore.
"Land and Sea shall part, the middle can not hold."
This tells me that the Seldane and Undine are out of the way, or at least not as major players as they were previously.
"Air and Fire shall wreack havoc, and Night shall fall."
As clear a reference to Ur Sylph and Ignae as I can figure. The former presumably got out of his prison and went on a Roaring Rampage of Revenge. The latter... perhaps Old Ignae the Trickster saw his chance to grap for power with the East and West out of the way?
"For the powers of the Four Directions shall form a Fifth.
The Four parts of the Opener of Ways, Made One.
This shall be the Key to the Fifth Element."
The Cronla is involved (big surprise). Although since we already reassembled it in Cythera 1, it raises the question of how it got broken into pieces again?
And then there's always the wildcard Tavara.
His journal indicates that he realized that Alaric's power was as beyond him as he was beyond the Mages, but that he also realized that (as an immortal Lich) he could bide his time since Alaric was still mortal. With Alaric dead, I can't imagine Tavara not finally making his own moves for power and revenge after centuries of patient waiting.

Anyway, how did the player even get back to Cythera? Magpie summon him?
Or did the interdimensional disruption caused by Cythera's breakup cause the player's house to land in Catamarca like Dorothy Gale from The Wizard of Oz?

I had a great idea for an intro/tutorial level
You're going about your house, on Earth, picking up basic gear based on your starting class, with the implication that 'ol Bellerophon has been keeping their skills sharp with extracurricular hobbies (for example, maybe instead of a sword maybe you have tennis racket). You go outside to check the mail, and then you have a sudden screen transition.

I wonder how much later the hypothetical Cythera sequel would've taken place?
Kind of curious as to the fate of our companions
I know that Cythera's years are shorter than ours and humans live longer there because of some magical property of the land (mages especially)
But I'd give good odds that Meleager is dead from old age (or at least permanently retired)

Anyway, as for the player's companions...
Depending on how long the timeskip has been, Meleager is probably retired or dead (RIP). Hector, Aethon, and Timon all seem pretty young, though. People live longer on Cythera, both because of the shorter years and because of some magical property of the land itself, and Mages like Timon can live even longer (just look at Master Librarian Selinus, who's probably been around since Pnyx was founded).
Always thought it would be cool if Demodocus could join the player. It would certainly be easier for him to justify in the sequel, since it'd be hard to continue his travelling bard act otherwise with Cythera's breakup.
Anyway, concerning Demodocus as a potential companion, my thought concerning him as a bard would be implementing him mechanically as a caster, with a list of reskinned spells like Rally and Awaken as his 'songs'. He'd also be a good source of 'Ask About' lore.
There's also the possibility of getting Omen as a companion, and wouldn't that be a fun plot twist? 'The Friend That Nobody Likes'.
Step One: Re-Corporealize the Incorporeal Undine Spirit.
"At great price to myself I come to you, as a vision, to warn and guide you, protect and teach you."

I got the impression that whatever they did means that they can't just shapechange into whatever, whenever anymore. To become a vision, they sublimated into a sort of ephemeral mist.
Anyway, they would certainly be very salty (ha, sea puns!) about the player's actions in the previous game; destroying their Master by purifying the Cronla and ruining the Undines' plans, and all that. But under the circumstances, they might swallow their pride and ally themselves with the player or else risk losing everything to the current catastrophe.

Unrelated, I noticed a dummied-out line in Magpie's dialogue that caught my attention:
(Asking about Jhiaxus) "Many people have many motives, not all bode well."
Combine this in the context of another line:
"Magpie sees better than Sabinate or Jhiaxus, but this is unseen.
Sabinate and Jhiaxus have their own motives - remember this."
I'm starting to suspect that Jhiaxus' motives for eloping with Jinrai were more selfish than we were lead to believe. Perhaps he privately disagreed with the decision to seal the corrupted shard of the Cronla away in Maayti, and by siding with an Undine he hoped to harness it's power for himself?
Certainly, it's a curious omission that Jinrai's spirit claims you can trust her son, but implicitly does not say that you can trust Jhiaxus.
"You must learn who your enemies are, and who are your allies, but in the end, you can only trust yourself, for all others are blinded by their truth.
There is one you can trust, who is our offspring. But in the end, do not be blinded by a truth which is not yours."

Sfiera (quoting Ignae): "Jhiaxus attempted to go beyond what he is, and he pays the price for that.
I have respect for the attempt, but scorn for the folly."

That honestly says just as much about Ignae as it does about Jhiaxus

Under-used feature: Bellerophon actively responding to NPC dialogue in the conversation window
Could be used to impart some personality on the player-character (by which I mean any)

Hypothetical: Bellerophon starts all obsequious and polite, but becomes increasingly snarky and irreverent as they are confronted with obstacles. Eventually, towards the end of the Main Quest, they are clearly Done With This(tm), and outright demand that a plot-critical NPC just give them a straight answer instead of leading them on with cryptic comments and arbitrary errands.

Thought on the Crolna:
When the shards under Catamarca and Maayti are picked up, the player experiences sensations related to their effects. For the former, a feeling a sickness relating to the plague; for the latter, a sensation of corruption relating to Maayti's sinking.
We don't get anything like that from the other two, presumably because they are given to us instead of purified by claiming them.
Presumably, Pelagon exploited this loophole to slip us the last corrupted shard of the Cronla without us realizing. But presumably, the same thing happened as with the first two when the shard at the Headwater Ruins was found by Timon (not that he's talking about it).
The Crolna made Maayti sink, becoming a swamp. How did the shard at Headwater (presumably) destroy that Seldane outpost?
The fact that it was found there at all is very telling.
There's also this dialogue from Jinrai:
"Consider the facts, young mortal, and be set free by the truth. The ruins that were built by the Seldane - that is fact.
The ruins that were destroyed - that is fact. Ask yourself how, ask yourself why, ask yourself who.
And for what purpose was this done? With what tools was this done? And how are those tools used?
A tool is neither good nor evil - it is but a tool. It is in the hands of the wielder that a tool's purpose is determined."
Fuzzy on the timeline of Maayti sinking and Jhiaxus eloping with Jinrai
I'm inclined to think that the sinking happened first, since he was entrusted to the Key to the Right Post when the Crolna shard was sealed away
I do think that the place where the Crolna shard was sealed was originally some sort of shrine or protective vault. The setup is far too elaborate to be something that they just built when they abandoned Maayti (and the fact that this part didn't sink makes me wonder if it was constructed with the power of the Crolna in the first place).
You wouldn't want just anyone to have access to a tool of ultimate power. Which makes it all the more curious that the Undine somehow corrupted it anyway.
Could be that Jhiaxus and Jinrai were together longer than anyone thought.
Jinrai sent in to manipulate Jhiaxus and ultimately corrupt the Crolna, ultimately falls in love with Jhiaxus for real anyway.

453 said: We also know that the Undine can use time-magic, but so far the only confirmed case of that is them turning some wine sour. Could the "corruption" or the plague be caused by some kind of time-related magic?

Possibly. Accelerate the natural process of erosion over time; something which the Seldane may have previously used the Crolna shard to hold at bay.
Although it may not have been the only catastrophe unleashed on the self-proclaimed City of Truth
Imagine, if you will, a plague like in Catamarca spreading through the Seldane population of Maayti
Maybe that's why there are so few left...

I find it interesting how Magpie/Bahoudin has reconciled the contradictory halves of his nature
The Seldane are all about Truth; immutable, unchanging
The Undine are, well, the opposite; as changing and chaotic as the Tides
Bahoudin, or rather Magpie, is a Fool; a teller of Stories.
And what are stories if not more than true?
Stories do not simply tell us that monster exist; the tell us that they can be beaten.

Having slept on it, some more thoughts about the Cythera 2 scenario:
Your ultimate goal is to reach the LKH; specifically, the Brazier Room. Although this isn't clear from the start.
You can't actually reach the LKH directly from the starting fragment, which contains just Cademia and Odemida. Directed Nexus doesn't work (or doesn't take you to the LKH Nexus Room anymore). You have to circumnavigate the fragments of the island clockwise to actually get there.
Short-term goal on the starting fragment is finding a way off to the next one. The only people who could maybe help you are the Great Houses, but there is a complication in that the two who owe you a Debt from the previous game (Nicander and Strymon) are on the decline, and Atussa and Dodona are currently ascendant. Eases the player into the new status quo, now that Alaric is dead and his government is crumbling.
Newcomer House Pelops used the tens of thousands of Oboloi he earned from the Flax trade to seize control of the local agriculture with a tyrannical iron grip 😛
Besides Magpie, Hadrian has also moved back to his hometown of Catamarca with his wife and son. Distraught from his failure to protect Alaric, the LandKing's former Captain of the Guard has started drinking his days away. Emesa works as a cook in the Green Goat. Hector, older and wiser, is both surprised and glad to see the player, and joins the party because he just can't bear to stand around doing nothing.
Once you somehow (?) get off the initial starting island/fragment, you reach Cademia and are introduced to more drastic changes. Beyond the political upheaval, the crack in the earth that could be seen in southern Cademia and in the sewers in Cythera 1 has now grown into a vast chasm that splits the city nearly in half. If it's a volcanic chasm, then it could even be an opportunity to re-introduce Ignae.