It burns.

Killian has known darkness before, he thought he has known the blackest parts of a man, but this – this is something else entirely. Because this is not just his darkness. This is a darkness as old as time that is burning through his veins, filling him with the hatred and rage of hundreds of Dark Ones unable to turn away from the temptation of the dagger, of evil that has filled worlds with hate and sorrow and anger. And he drowns under this black pain until all he can feel is the burning of his soul, until he loses semblance of self and his last conscious thought is that death would be a welcome companion.

When he wakes, the sound of death is beating through his heart and he grimaces at the irony. He's not dead – yet death is running black in his blood, in every breath he takes, in everything he sees. There's also a lot of pain, in his limbs, in his heart, in all the spaces in-between. He wonders, when it is over, whether there will be anything of him left. He doesn't know whether it would better or worse to have a part of him in the monster that he will become.

He wishes he could drive the dagger deep into his chest, to end what he will become before he becomes it. But he can't. Because he knows now that he has become the Dark One that all the darkness inside of him must be tethered to a soul and he rather continue burning in agony than allow Emma Swan to carry this burden. So he tucks the dagger safely into his coat and stumbles into the shadows of this unknown world he has found himself in.

Night tumbles into night into night. And it's all too familiar but not. The loss of time, the loss of self, the fall into darkness. He knows this – but not this. It doesn't matter though because before, he didn't have anything to live for and now, he does this for Emma, Emma, Emma. And he wants to destroy and burn and rage but the anger in him is not really his own, the dark impulses in him are not really his own, and he just has to hold onto the part that belongs to Emma to hold in the dark power burning his fingers from inside out.

He keeps to himself, to the shadows. When he was still a man, he prided himself on getting to know the lay of the land in any port he made, in any realm he crossed. But here, he stays away. It's already unbearably hard to hold onto the part of himself that remembers what love is, that remembers green eyes and hair like the sun. He doesn't even realize that he had transported himself to the fishing village where he grew up as a boy. Of course, the village he had known has changed since he was a child, weathered far too many storms, lost much to the sea. But in one of his final moments before becoming the Dark One, he had cried for home without knowing. So he is here, becoming a shadow, wandering amongst broken trees, along a colorless coast, and here he thinks he will wander until all worlds are no more.

But one day he hears a child cry and he is running towards the sound before he has even given it a second thought. She's small, thin, but spry, holding onto what little she has in a threadbare bag close to her chest, but she's no match for the two men hovering over her who don't care if a child starves as long as there is food in their bellies.

It's almost instinctual – reaching into the closest man's chest. He can feel everything – the man's life force pulsing underneath the tight grip of his fingers, the underlying fear causing this stranger's heart to race, but even more than that, Killian feels the power of having complete control over someone else's life. And death. It is enthralling. He squeezes the heart in his hand. The man's scream is unbelievably satisfying. And Killian can feel himself grin for the first time in memory. He wants to hear that scream again. He wants to cause it. And without knowing, he lets green eyes and reluctant smiles, blonde hair and white light, go. This is the true start of the fall.

But then the child's voice saves him.

"Please, no, sir. S'not right."

He looks down to find the little girl pulling at his sleeve, her large eyes pleading mercy though she is the one who needed saving. Killian thinks he knows someone else like that, who saves others at the expense of themselves. But he can't remember the face nor the name. He doesn't realize he has forgotten, that he had let her go when he wasn't holding on – because the thing with forgetting is, you can't remember when it's already gone. Killian shakes himself a bit, feeling despair at something lost but not knowing what, and when he looks around, he is surprised to find his arm elbow deep in a man's chest. He can't really recall doing it but then he feels this dark pulse ripple through his arm. It doesn't feel like this magic is even his own – more like, it has its own life or thousands of them. It feels hungry, angry and all too foreign – and Killian lets go of the heart in his fist and pulls his arm back.

The other man blinks at him, as though surprised he is still alive, before realization he is free seems to kick in and he's running. The thought of stabbing the man in the back makes Killian's blood hum. He reaches for his dagger but then a small hand slips into his and the rising magic in him seems to settle once again.

"Thank you," the girl is saying.

"I wanted to kill him."

"You don't have to."

"But I wanted to kill him," he finds himself pleading, confessing, crying to the child. "I wanted to kill him, I wanted to kill him, I wanted to kill him." And by the end, Killian isn't sure if he had wanted it but someone, something wanted it. And he has to hold onto the child's hand until the magic quiets and night has come and he falls asleep.

When he wakes, the girl is sitting next to him.

"You should run."

"I have nowhere to go."

The word orphan rises in his mind and a familiar yet foreign feeling tears at his heart. "I'm not a good man. I'm not sure I'm even a man anymore. There's dark magic in me," he tries to explain. "It wants to burn out of me." He hadn't known before but using magic makes him want, want, want so badly – to do more magic, to use it to commit violence, to destroy.

"That wasn't the man who saved me last night," the girl says as she looks unblinkingly into his eyes.

Killian tries to think of the man he was before but he can't remember. He can only hold onto what is in front of him. It makes him shake, to know something is forever lost, that he has let something go without even meaning to, that it has been replaced by the magic beating inside him, wanting to darken everything. The thought of being lost at sea comes to mind unbidden but he doesn't know why and it makes him feel even further adrift. "What's your name?" he asks the girl, seeking something real to hold onto.

"I don't really have one," the child shrugs, her thin shoulders poking through her threadbare clothes. "I can't remember what my mum used to call me before she left so I make up a new one each full moon." She leans in closer to him and he sees some of her nonchalance fall away. "You could give me a name, if you'd like," she smiles shyly.

He doesn't recall having any children but he understands immediately. She seeks an anchor too. "Can I call you Leia?" he asks. He doesn't know where the name comes from but it sounds right the moment he says it. And when she smiles and nods in acceptance, he feels peace for the first time in memory.