I'm rereading ToG for the first time in years and I can't help but notice some similarities between this series and ACOTAR and CC, and I wonder if these could become relevant on a grander scale for Twilight of the Gods.
Damaris/Ataraxia/Gwydion
Damaris is the legendary sword of the ancient King Gavin. The sword he had wielded in the fierce wars that had almost ripped apart Erilea. The sword that had slain the Dark Lord Erawan (although, if I remember correctly Erawan is still alive and doesn't die until the end of the last book, but I believe he was still killed by Dorian wielding Damaris), and the sword that was used by Celaena to kill a ridderak.
Ataraxia is the Made sword of Nesta Archeron. The sword that can kill unkillable beings like Lanthys and Vesperus. The sword that was able to bind Lanthys to his physical form, and the sword that the Prison inmates now fear.
Gwydion is the Made sword wielded by Bryce Quinlan and now Nesta Archeron. The sword that can kill unkillable beings like the reapers in CC (and I believe Bryce used to kill the kristallos). The sword, when combined with Truth-Teller, can create a black hole, which Bryce used to throw the Asteri in. The sword was wielded by the first and only High King of Prythian to bring about a millennium of peace and unity to Prythian.
If Twilight of the Gods is a megacrossover where they have to fight together to defeat some intergalactic evil like the Valg and the Asteri, all three blades would be incredibly useful since they can be used to kill unkillable beings, Dark Lord's, and gods.
Valg/Asteri
Maybe I'm wrong since I've only just finished book one of ToG in my reread, but I'm thinking the Valg and the Asteri may not be the exact same, but are still something similar or related. I remember the Valg having black blood, and when Nesta killed Vesperus, the Asteri also bled black. I remember the Valg were more like possessing people, whereas the Asteri are practically gods, but I think the big baddies in Twilight of the Gods will be something similar to both or maybe the creators of both.
Mother Goddess/The Mother
In ToG, the Mother Goddess was a spirit from another world who found Erilea in need of form and life.
In ACOTAR, the Mother is a being from another world who used the Cauldron to bring forth life into Prythian.
I'm wondering if the Mother Goddess from ToG and the Mother from ACOTAR are one and the same, and how Nesta's connection with the Mother may pose some greater significance as ACOTAR continues, and even into Twilight of the Gods. It could be that when the worlds come together to fight some intergalactic Valg/Asteri, the evil may destroy worlds, and maybe Nesta can reMake those worlds anew? Or fix everything to what it was prior to the Valg/Asteri takeover?
Ridderak/Hounds/Kristallos
In ToG, ridderak are demons from another world that are being summoned into Erilea by Cain, using Wyrdmarks and Wyrdgates. It's always mentioned that they were summoned out of pure darkness and partially ate their victims. Nehemia used Wyrdmarks to send the demons back to their world and used Wyrdmarks to protect Celaena from them; the Eye of Elena was an amulet that was also used to protect Celeana.
In ACOTAR, there are the hounds or beasts from the Hewn City that used to run in the Wild Hunt. When Lanthys was trying to seduce Nesta, he showed her a vision of them ruling with the Dread Trove with the Hounds at their feet. We don't know much about them besides that, but Bryce mentioned in HOFAS that they reminded her of the kristallos from her world, which could suggest that the hounds are demons from another world that had been summoned to Prythian, maybe by the Asteri when they ruled? I also want to mention one moment in ACOSF that is never explained: one day in the library, Nesta was staring into the pure darkness at the bottom of the library, and she felt beckoned by it like it was calling her name. Gwyn helped her escape using the priestesses Invoking Stone for protection. Later, Nesta mentioned to Cassian that she felt as if something had been trying to eat her. It just makes me wonder if someone was trying to summon a demon to kill Nesta.
In CC, there are the kristallos, which are demons from Hel that were being summoned using black salt (if I remember correctly). I can't recall if the amulet Bryce wore from Jesiba was used for protection against them or if it was just her starlight, but I do wonder if there is some connection between the Eye of Elena, the Invoking Stones, and Bryce's amulet. And if maybe the ridderak and hounds are also demons from Hel?
Elena Galanthynius Havilliard/the Mother/Danika Fendyr
Queen Elena guided and protected Celaena; the Mother guided and protected Nesta throughout ACOSF (and they have some sort of connection); and Danika has guided and protected Bryce throughout CC.
Starborn
We know Bryce is Starborn, and all signs point toward Nesta being Starborn, but I'm wondering if Queen Elena (like Queen Theia) was Starborn, too? In ToG, it mentioned golden light erupting around Queen Elena and golden light bursting from her palm, and it mentioned her skin glowing. Bryce commands light and shadows; her starlight being referred to as a radiant sun, and Bryce has glowed multiple times because of it. Nesta also has multiple references to glowing, and ACOSF and HOFAS may have foreshadowed her having starlight that she doesn't know about. I don't remember enough of ToG to know if Aelin ever presents any signs of being Starborn, though.
Wyrdmarks/the Harp/the Horn
Since Twilight of the Gods is rumored to be a megacrossover where the worlds of Erilea, Prythian, and Midgard team up to destroy whatever intergalactic enemy is threatening their worlds, Aelin, Nesta, and Bryce are going to be instrumental since all three seem to be able to world-walk.
Aelin can use the wyrdmarks to create a portal into other worlds; Nesta can use the Harp to travel to other worlds; and Bryce can use the Horn to open portals into other worlds. I don't think it's meant to be coincidental that these three have so many similarities in characteristics, passions, and storylines.
