Yaz

First, it's helpful to get some context for what we know (for sure) about the Prison:

It was the land of dusk (not a Court in the way Prythian currently has courts).

After the events with Fionn, Theia, Helena, Silene, and Pelias, the land was mostly abandoned.

When Silene returned from Midgard, she created the Prison in order to hide the Harp, using the monsters she put there to deter anyone from looking for it. Silene decided if this place was seen as cursed, then let it be cursed.

We also find out that Silene left her portion of Theia's light under the Prison, which Bryce then took.

There is also a large cache of firstlight remaining under the Prison.

When Bryce used Truthteller and Gwydion/the Starsword to heal Avallen, Pegasuses appeared again.

Avallen and the Prison are in "thin" spots in the universe that make it easy to travel from one planet to the other (fwiw, this idea is not unique to sjm. See: Stephen King.) These spots are identifiable by the mists that surround them.

These thin spots are also on the nexus of ley lines, where energy flows.

It stands to reason that when Bryce "unlocked" Avallen, the energy and magic that it now experiences will flow to other places along the ley lines, IE the Prison. It's also implied that the land keeping the power imprisoned is one of the reasons it grew sick.

Bryce's actions in hofas have implications for Prythian. While the above is related to the Prison, we also have:

Nesta now has possession of the Starsword/Gwydion

Azriel's reaction to Truthteller and the Starsword being together

The 8-pointed star (more on that later)

Part two: what we know based on ACOSF

So based on this information, we need to go back to acosf and look at what sjm left for us. 

The main thing to keep in mind is that Nesta found the Harp in the Prison, and that it was laying on an 8-pointed star. 

One of the main dangling threads from acosf - that we know to be canon, that is not a theory or supposition - is that the Illyrians and the Valkyries are going to continue training together. We know that Mor is interested in training with the Valkyries. From hofas, we know that Nesta is every bit as well trained now as she was in the months since acosf.

Now, there are a couple of partially-fulfilled statements from acosf that I think are relevant here, in addition to Valkyries and Illyrians continuing to train.

The first is the wish that Nesta made on the friendship bracelets. 

"I wish for us to have the courage to go out into the world when we are ready, but to always be able to find our way back to each other. No matter what." (chp 59)

We know that in the Blood Rite, the second half of that wish was fulfilled. The first half has not been fulfilled yet. That gives us very good reason to assume that the first half will be fulfilled.

All three of them, Nesta, Emerie, and Gwyn, will go out into the world at some point in the future. 

There is another, much larger implication that was made in acosf:

Nesta smirked. “If we are to be Valkyries born again,” she said, “maybe we should combine the Illyrian and Valkyrie techniques.” She’d meant it in jest, but the words rumbled through the space, as if she’d spoken some great truth, something that made fate sit up. Azriel turned to them fully this time, eyes narrowed. Like those shadows had whispered something to him. A chill breathed down Nesta’s spine. Cassian stared into their faces. Like he beheld something he hadn’t seen there before. (chp 44)

And the later on:

Gwyn whispered, “I am the rock against which the surf crashes.” Nesta straightened at the words, as if they were a prayer and a summons. Gwyn lifted the blade. “Nothing can break me.” Cassian’s throat tightened, and even from across the ring, he could see Nesta’s eyes gleaming with pride and pain. Emerie said, “Nothing can break us.” The world seemed to pause at the words. As if it had been following one path and now branched off in another direction. In a hundred years, a thousand, this moment would still be etched in his mind. That he would tell his children, his grandchildren, Right then and there. That was when it all changed. Azriel went wholly still, as if he, too, had felt the shift. As if he, too, were aware that far larger forces peered into that training ring as Gwyn moved. (chp 60)

SJM used similar phrasing in the same book for which we know the consequences: 

Strike after strike, and Cassian could have sworn the world paused as she unleashed herself with the same intensity she brought to training.

This is when Nesta is Making the weapons, which we find out later is actually a significant moment, not just Cassian being hyperbolic about how great his mate is. Then, when Nesta is using the Mask and Harp to heal Feyre, the world also pauses. This phrasing is used when something important is happening - even if we don't know what the implications are, yet.

Given that we know for sure that the Illyrians and the Valkyries are going to continue training, and there are loose threads because we don't know the implications of fate/the world standing up at Nesta's, Emerie's, and Gwyn's statements and/or actions, there is a very, very good chance that the Valkyries will continue being a big part of acotar. 

My final point about the Valkyries is that in myth, they rode horses through the sky - not Pegasuses because those are from Greek myth, and Valkyries are Norse. But they fly through the sky on horses nonetheless. (This is literally the only piece of evidence I have coming from outside the books.) Pegasuses are connected to Avallen and likely the Prison. We know that Helion keeps some, but they are struggling to breed/thrive. (We also know that sjm loves to take what she wants from myth, so it’s not a stretch to think she’d shrug at the Greek/Norse distinction.)

All of this together tells me that the Valkyries have more story coming, and it is connected to the Illyrians'.

Part three: The 8-pointed star

A common thread between both series is the 8-pointed star. There are a few ways in which it is used:

Nesta and Cassian's bargain tattoo in acosf. They both had this tattoo on them - an Illyrian and a Valkyrie. 

Bryce also has the 8-pointed star on her chest that glows when she is near people who will aid her or who are part of the Starborn line. When she took the piece of Theia's light, it went into her star and powered her up.

The Harp was resting on an 8-pointed star in the Prison, where Silene left it.

In HOFAS, Bryce put Truthteller and Gwydion into the slots of an 8-pointed star in order to revive Avallen.

When training, Cassian teaches the Valkyries the 8-pointed star sequence. This is a series of moves that they make with a sword, and is an Illyrian technique. 

Cassian walked her through eight different cuts and blocks. Each was an individual move, he’d explained, and like the punches, they could be combined. (chp 38) “I’d thought today would be a good day to integrate the eight-pointed star, but if you’re already complaining, we can wait until next week.” (chp 44) Nesta lifted the sword and executed a perfect arcing slash. Her weight shifted to her legs just as she flipped the blade, leading with the hilt, and brought up her arm against an invisible blow. Another shift and the sword swept down, a brutal slash that would have sliced an opponent in half. Each slice was perfect. Like that eight-pointed star was stamped on her very heart. (chp 50)

And finally, at the end of HOFAS, Bryce gives Gwydion to Nesta and tells her to explore the 8-pointed star:

“I think that eight-pointed star was tattooed on you for a reason. Take that sword and go figure out why.”

Note that it’s not just a matter of the star, anymore. Both Cassian and Nesta were tattooed with it; Bryce used Gwydion and Truthteller to activate the star in Avallen. And now, Nesta is in possession of Gwydion with knowledge about the Prison and a connection to the star. There are elements coming together, and those elements are connected to both Illyrians AND Valkyries. 

My thinking is that the 8-pointed star is the symbol of the dusk land, the Starborn Princes in Midgard (Theia) and in Prythian, of the first and only High King. If that land is where the Valkyries will be reborn and where Starborn power is from, and we know it is the source of a huge cache of firstlight, then that star is a symbol of what has been lost - and what is about to be revived.

So now the question is - what part will the Valkyries and Illyrians play?

Part four: What might happen to the Prison?

To sum up the above, and adding on a couple of small points that don’t fit elsewhere:

We know that the Illyrians and Valkyries will continue training

We have very heavy-handed phrasing around the world/fate paying attention to the idea of the Valkyries being reborn and working with Illyrians.

We have the connection between Valkyries, Illyrians, and the 8-pointed star because it is also an Illyrian sword technique that is being taught to the Valkyries.

We know that the Prison is going to go through some changes akin to puberty.

In addition, we have Gwyn being allowed to write the Valkyries into the books she is researching. 

SJM has also said that Nesta’s story is going to continue.

Since we know that the Prison is going to change and there are these characters and groups poised for action - I haven’t even touched on Ramiel and the Illyrians being created by the Dagsteri, Azriel and his connection to Truthteller and Enalius, and his reaction to the TT/Gwydion, and will do that in a separate post - we can make some predictions about how that might look. If it’s going to make sense, sjm has to think beyond the magic system that she has… sort-of established, and past the involvement of individual characters. There are a few things to take into consideration with the Prison.

It is very likely that Pegasuses will return to the island as it is suffused with magic and energy again. 

There are also other, unforeseen magical consequences as the magic flows back into it, thanks to the ley lines being “unblocked” by Bryce. 

It may become easier for people/creatures to travel between worlds, given that it is a thin place that has been "unlocked". 

The Prison is still full of prisoners! They are monsters that Silene gathered to hide the Harp, but... does that mean they just get released? Get slaughtered? Do they now have access to the power of the island? What is going to happen with them? 

The High Lords cannot all be trusted to stay within their own courts, minding their own business. Beron is the most obvious example, as he has his eye on Spring while Tamlin is Suffering. 

If there were another court established, one that sits on a huge reserve of firstlight, that could be a huge point of contention amongst the courts. Even if the High Lords don’t want it for themselves, they wouldn’t want anyone else to have it on the chance that one of them would use it against the others. In acomaf, Rhys explains that the Prison is keyed to his blood and that he has jurisdiction of it; however:

“Do all the High Lords have access?” My words were so soft they were devoured by the dark. Even that thrumming power in my veins had vanished, burrowing somewhere in my bones. “No. The Prison is law unto itself; the island may be even an eighth court. But it falls under my jurisdiction, and my blood is keyed to the gates.” (chp 18)

We don’t know yet what that reserve of firstlight is going to mean for the island.

To me, it makes sense for us to have a more neutral third party come in. One who doesn’t have ties to a specific court, but could act in all of their interests. 

Enter: the newly reformed Valkyries. 

I have had a personal headcanon that the Valkyries, once fully established, could create another political/martial entity in Prythian that can help balance the power between all the courts, and provide support when needed. This is how they worked before, which Cassian talks about in acosf: 

“The Valkyries fought when even the bravest males would not. The Illyrians tried to forget that. I fought against males who were my superiors, arguing to help the Valkyries. They beat me senseless, chained me to a supply wagon, and left me there. When I came to, the battle was over, the Valkyries slain.”

Valkyries and Illyrians don’t have the best history, but given that Cassian tried to help them, and that they are working together now, this could be a way of righting a wrong. It could help to explain why fate/the world is taking note. 

The Valkyrie ethos makes sense for this sort of neutral position, too:

“A clan of female warriors from another territory. They were better fighters than the Illyrians, even. The Valkyrie name was just a title, though—they weren’t a race like the Illyrians. They hailed from every type of Fae, usually recruited from birth or early childhood. They had three stages of training: Novice, Blade, and finally Valkyrie. To become one was the highest honor in their land. Their territory is gone now, subsumed into others.”

An improved Valkyrie force, especially if they continue learning Illyrian techniques and recruiting from women across Prythian, could be a big factor in upcoming conflicts with Kochei or any other villain sjm comes up with. They would ensure that the firstlight would be used fairly, so that no court is advantaged or disadvantaged unfairly. It would continue the threads that sjm has left for us, while also giving us space to explore questions that have yet to be answered (such as Azriel’s connection to Truthteller and Enalius). While I think that Nesta would keep her home in the House of Wind, the Prison island would be a good place from which the Valkyries can work - both guarding the monsters that are there, and keeping the firstlight safe.

I believe that Nesta will be the most important character when it comes to reviving the island; while it is heavily implied that the island is already going to have access to its powers thanks to being impacted by Avallen's healing - it is likely already on its way to healing - Nesta with her connection to the 8-pointed star, the Harp, possession of Gwydion, and the Valkyries can help bring stability to the place.