Nesta and the Prison - Dusk Court.
Let’s discuss why Nesta is the only one connected to the Prison/Dusk Court, and how she has been linked to it in not one, but two books in different series (ACOTAR and CC):
This is how the magic works. Theia (Starborn - World - Walker) chose the land, and the land chose her right back. Then, from her magic, the very same magic that tied her to the land, she gave a piece to each of her daughters.
"My father became High King, and my mother his queen, yet this island on which you stand, this place...my mother claimed it for herself. The very island where she had once served as a slave became her domain, her sanctuary. The Daglan female who'd ruled it before her had chosen it for its natural defensive location, the mists that kept it veiled from the others. So, too, did my mother. But more than that, she told me many times that she and her heirs were the only ones worthy of tending this island."
"And with the Daglan gone, as the centuries passed, as the tithe was no longer demanded of us or the land, our powers strengthened. The land strengthened. It returned to what it had been before the Daglan's arrival millennia before. We returned to what we'd been before that time, too, creatures whose very magic was tied to this land. Thus the land's powers became my mother's. Dusk, twilight - that's what the island was in its long-buried heart, what her power bloomed into, the lands rising with it. It was, as she said, as if the island had a soul that now blossomed under her care, nurtured by the court she built here."
“Pulling her daughters close, Theia flared with starlight. And in the small space between their bodies, Bryce could just make out Theia plucking a low string on the Harp. In answer, a star - akin to the one Bryce could pull from her own chest - emerged from Theia’s body. It split into three shimmering balls of light, one drifting into Silene’s chest and another to Helena’s before the final one, as if it were the mother from which the other two stars had been born, returned to Theia’s body. For a moment, all three of them glowed. Even Truth-Teller, in Selene’s hand, seemed to ripple, a dark countermelody to how Gwydion flashes in Theia’s hand, its light a heartbeat. “She gave us what protection her magic could offer, transferring it from her body into our own using the Harp.”
Theia's magic on the land always manifested itself like an eight-pointed star.
“Silene studied the spot where she knelt on the eight-pointed star in the center of the room. The only adornment. She slowly set the Harp atop the star.”
Absolutely everything involving the Dusk Court (the Prison) revolves around the eight-pointed star logo, which is the sign of the Starborn. Nesta gets her bargain tattoo in the shape of an eight-pointed star, so it is clear that Theia’s and the land’s magic chose her and marked her so that the magic responds to her. She found the Harp on top of an eight-pointed star on the ground and was allowed to pick it up despite the heavy wards. Even then, The Prison itself didn't seem to want to let Nesta go:
"The words tumbled out as Nesta waded back through the ward-heavy cavern, feeling that center spot, the star at its heart, like a physical presence at her back. Those vast, light hands seemed to pull at her, trying to make her return, but she ignored them."
There was also this scene (which I find very interesting), where the Prison in Prythian answered to Nesta instead of Bryce. It seems Bryce has the connection to Helena’s side of the caves in Midgard, while Nesta has the connection to Selene’s side in Prythian:
“The lowest spike on the star extended down, right in front of Bryce. So she laid a hand on the metal and pushed. It didn't budge. Nesta stalked to Bryce's side, tapping a hand on the metal. A dull thud reverberated against the cave walls. "Did you really think it'd move?"Bryce grimaced. "It was worth a shot."Nesta opened her mouth to say something - to make fun of Bryce, probably - but was silenced by groaning metal. She staggered back a step. Azriel threw an arm in front of her, blue light wreathing his scarred hand.”
Notice how the doors opened for Nesta and not Bryce? Because the land in the Prison chose Nesta. See how she can just walk into any room she pleases, no matter the wards??
“At first, nothing happened as Bryce stood atop the eight-pointed star. “Well—“ Nesta began. Light flared from the star at Bryce’s feet, from her chest, merging and blending, and then a hologram of a dark-haired young female— High Fae— appeared. As if she were addressing an audience. Bryce knew that heart-shaped face. The long hair. “Silene,” Bryce murmured. “From the carvings?” Nesta asked, and as Bryce glanced to her, the warrior stepped through the wards as if they were nothing. Like she could’ve done so all along.”
This is not because she’s “Made”, this is something very specific to NESTA. And yes, the Starborn are the descendants of Theia, but Bryce and Nesta seem to be Worldwalkers too. A different kind of ability. That’s why the lands in thin places answer to them.
“The black salt only repels the Asteri; the mists repel everyone else. But certain people, with certain gifts, can access the power of thin places—on any world. World-walkers.” Aidas gestured gracefully to Bryce. “You are one of them. So were Helena and Theia. Their natural abilities lent themselves to moving through the mists.”
So, it is Nesta’s worldwalking abilities that ties her to the Prison, not only her being Starborn or Made. It’s why this particular side of the plot belongs to Nesta, and no one else. The eight-pointed star was Nesta’s. The wards on the Prison open for Nesta. She can even allow other people into the warded rooms with her powers, like she did for Azriel in HOFAS. There is no strong canon evidence at all to point out that the Prison would somehow answer to anyone else just because they’re Made. It is Nesta’s story, and it’s not over yet.