I know this sounds insane, but...
Danika Fendyr is the 7th Asteri, and quite literally, lives on inside of Bryce's heart.
SPOILERS FOR CC AND ACOTAR!
I have long since believed that when a character in the SJM universe dies, they are reincarnated into the next world.
The most solid proof of this is the Bone Carver. When he first meets Feyre, he asks her multiple questions about her death; whether she saw a "portal" into a new world, and if she was given a new "body."
Then in HOSAB, the concept of going somewhere else when you die is brought up several times.
For example, Bryce questions it:
And even the River Queen suggests that there is a new world after death:
This quote cements it further; the way for one's soul to travel in and out of the world, is through birth and death.
And, let's not forget Cassian's famous quote about finding Nesta in the "next world," and the "next life."
Yet most importantly of all, in the ACOTAR world, we witness Starfall. It is said to be souls migrating.
This is further backed up by CC2, when we learn that the Asteri have been stealing 'secondlight' (a term for people's souls), which aligns with Rhys's observations that the stars in Starfall have been dwindling in number's each year.
But, for the purpose of this theory, the most important point is this; everyone's soul is literally a STAR.
It's for this reason, that I believe everyone possesses a star in their chest; it is their SOUL.
So, what is Bryce's power then?
We are lead to believe that Bryce's power - the Starborn power - is a star in her chest. That's true, but I don't think it's the full picture.
If our souls are stars, then I believe that Bryce's power is simply being able to wield the light of her own soul. Essentially, Bryce can pull her soul out of her own chest.
As further proof of this, recall that the very first time we see Bryce use her Starborn power, it was said that a "lock" clicked open in Bryce's HEART and SOUL.
And I mean, look at Bryce's chest on the cover of HOEAB:
With this in mind, and knowing that reincarnation is highly likely; Aidas mentioning that Bryce and Theia's light is the same "hue," and that "Bryce's light is Theia's light" - is very interesting.
Again, if souls are indeed stars, and the star that Bryce wields is the same as Theia's - this suggests that their souls are one and the same. That Bryce literally possesses Theia's soul; she is her reincarnation.
There's a bunch of evidence to point to this being correct, but the most pointed is the HOSAB scene in the gym; Bryce has a feeling that she is falling through "time and space;" but that she wanted to stay in "this body," and "this place."
But, as insane as this sounds - I don't believe that Theia is the only soul inside of Bryce's chest. I think someone else is there too...
I have always suspected that Danika was also someone powerful, reborn again. This suspicion grew stronger when I realised that the "ancient alphabet" that Danika used to tattoo Bryce, was actually wyrdmarks.
However, it was this parallel that cemented it for me;
At the end of HOEAB, Bryce looks towards the Bone Quarter and can see the 6 members of the Pack of Devils. However, the 7th member, Danika, is now gone.
What does this sound like...?
The Asteri. 6 remaining, the 7th gone.
I believe that Danika was a reincarnation of the 7th Asteri - Sirius.
In real life, Sirius was often known as the "Morning Star."
What does the name "Danika" mean...?
Further, recall that Bryce and Danika each traded their own souls to the Under King to save each other. I truly believe that when Danika died, her soul, or a part of it, *literally* lives on within Bryce's chest/heart.
And... this is HOW THEY DID THE DROP.
In HOEAB, it is stated that the Drop is the act of plummeting into your own soul;
Who does Bryce find when she does the Drop, right into her own chest (despite it being... impossible?)
And, right before Bryce ascends back up, Danika says "even if you can't see me, I will always be with you."
Bryce then says, "she had never been alone, she never would be - NOT WITH DANIKA WITHIN HER HEART" !!
Although you may argue that this was merely just a figure of speech - I don't think it is.
Because, recall that when the Prime of the Wolves witnessed Bryce racing around to defeat the demons at the end of HOEAB, he said that "one wolf remained" in the Old Square. Sabine assumes that he must be mistaken; that he is instead registering Danika's sword that Bryce is holding. But, the Prime of the Wolves looks at Bryce, and then points to his HEART AND CHEST, and then calls Bryce a "TRUE WOLF."
And again, in the next book, the Prime once again calls Bryce a wolf, whilst pointing to his chest/heart.
But he's not referring to Bryce,
HE'S REFERRING TO DANIKA!
And, who was Sirius the Asteri known as?
This explains why, after the Drop, Bryce seemingly inherited the *identical* power of the Asteri overnight (something I had already made a theory about - the resemblance was just uncanny).
It's because of DANIKA'S SOUL! (And likely also the Horn and the Synth; but, both were orchestrated by, you guessed it, DANIKA!)
This is why Jesiba told Bryce that she won't find any traces of Danika in the Bone Quarter; because her soul is literally within Bryce.
And, if you still don't believe it, then recall when Bryce found out that Baxian was Danika's mate. To present proof, Baxian revealed the tattoo Danika gave him; again, of the infamous words "through love, all is possible."
Bryce then says this - and the wording here is very important - the tattoo was "one last clue from Danika, to LOOK WHERE SHE'D STAMPED THE PHRASE."
Where had Danika put the tattoo?
"Through love, all is possible."
Through LOVE - through BRYCE'S HEART - the impossible has been made possible.
I think it was a literal clue; the heart and soul - where love resides - is where Danika has always been.
Interestingly, Baxian also tells us that Danika was trying to find a way into a "new world."
And where has Bryce just recently landed? Prythian. A new world.
The impossible, made possible.
I also believe that Hunt is the reincarnation, or possesses the soul of Thurr; who was a powerful God (that's for another theory post...). It's why Bryce says, countless times, that Hunt and Thurr look *identical.*
I am inclined to think that in some way, Thurr and Sirius, or Thurr and the wolves were connected; perhaps the wolves protected Thurr, or were his loyal servants.
Because that's exactly how the mythology around the Orion and Sirius constellations goes; Sirius was immortalised in the sky to keep watch, and guard Orion.
Perhaps it is not just Bryce that has been looking out for Hunt, but Danika too.