My take on Killian's end of Emma's attempt to contact him in the Underworld during 5x12.

"Killian."

He hears her voice.

It flows like honey and sunshine as she breathes out his name.

He sees her face, her skin rosy once more, her hair golden and flowing free like it was meant to be. He sighs deeply, ignoring the pain in his ribs as he drinks this version in, her image bright and shiny even as it flickers in and out of his vision. His Love, his Swan, his one bright and precious memory to savor among this damned and hellish eternity.

He simply listens as Emma begs him to talk to them, to her, not being able to do more for fear of his eyes being torn away from her beautiful mirage. From trying to remember every single fragment of green in her eyes, from attempting to count every freckle on her face, from imagining the feeling of her silken, lustrous strands wrapping around his hand. How can he speak while being engulfed in all that is pure and her?

He knows it won't last, this heavenly apparition that was granted to him. He doesn't know why or how, but he knows it is fleeting and he wants so much more; He wants the light and rich, pure goodness that is his Emma Swan.

He hears one of them coming for him, another of Hades's numerous demons intent on continuing his daily suffering, their heels clacking on the stone ground, the noise echoing in time with the stuttering illusion in front of him.

"Killian. We're here to help you."

There is no help for him now. He died to save them, to save her, and he would willingly die a thousand times more to keep them safe. That death is all that he knows now. This battered and bruised existence, it is his never-ending punishment. Night after night, one agonizing second after the next, his torture forever.

His tormentor grows nearer as he stumbles forward, drawn toward the agony in Emma's voice as she cries for him once more, her light finally flickering out as her apparition fades back into the darkness.

"Emma..." Killian pleas as she disappears from his view. His voice is raspy, throat raw and bleeding from it's continued abuse.

"Finally starting to come around, Hook?"

The deceitful voice of his tormentor rings out from the shadows, manipulative and as dangerous as his surroundings. He can hear it moving around him, the slight glances he is allowed furthering his agony as he spies the pale skin reflecting off of the one lone light he was granted when thrown into this abyss.

"I will n-never," Killian rasped, allowing his body to fall back down to the stone ground below him. "You are not her...never her..."

Coldness descends over his body as the figure slithers closer, sharp nails sinking into his face as his chin is forced to the side.

"Oh, my dear Captain...when will you learn? You don't deserve the Savior. I am what you deserve; I am what you allowed to happen. This darkness," the demon hisses, leaning in so the torch finally highlights its features, "is your making."

Killian's breath leaves his lungs in a laborious rush as he eyes the form above him, blood-red lips glistening as the infernal demon tempts him once more while wearing Emma Swan's face, her lovely hair stained a whitened silver to match the blanched skin she was adorned with while being afflicted with the Dark One curse.

"Now, shall we pick up where we left off?" It questions, Emma's sweet eyes filling with a abominable evil glint as their hand slides slowly down his torso, an excruciating pain immediately starting to radiate from his chest.

Killian throws his head back, his anguish-filled cries echoing off of the cavern walls while he tries desperately to remember Emma's flickering face, her promised words filtering through his mind.

"We're here to help you."