Feyre enters the chamber that holds the Ouroboros and is surprised to find it open to snow, wind, and moonlight. The mirror stands across the room in a bronze frame shaped like a serpent devouring its own tail, and at first it shows only Feyre’s ordinary reflection as she approaches it through the cold.

As Feyre studies the glass, she notices movement and seems to find a monstrous beast behind her, with claws, scales, fur, and tearing teeth. Feyre spins to attack with an Illyrian dagger, but the creature is not physically present. When Feyre turns back to the mirror, she realizes the beast is her own reflection: a vision of what exists beneath her skin and within her nature.

Feyre then truly looks into the Ouroboros. The experience leaves her drained, changed, and struggling to return fully to herself, but she survives what the mirror shows her instead of being destroyed by it. Having claimed the mirror, she is able to summon it when she enters the Bone Carver’s cell.

In the Prison, the Bone Carver immediately understands that Feyre succeeded. When Feyre demands that he honor their bargain and prepare for the coming battle, the Bone Carver reveals that he never needed the mirror for himself. He wanted to test whether Feyre was strong enough to face her entire true self without madness or collapse.

The Bone Carver explains that the Ouroboros shows people every terrible, ugly, and holy part of themselves, and that most who look into it either fail to understand what they see or are shattered by it. Feyre’s survival proves to him that she is worthy of his help. Though furious that innocent lives were made to hinge on his judgment, Feyre takes the Bone Carver’s hand without fear, and he agrees to leave the Prison and fight in the war.