Dark Swan: Death follows darkness

Prologue

The moment Regina was taken away by the darkness everyone froze, even the saviour.
"What's it doing?" Robin said, frozen where he stood.
"What darkness does...snuffing out the light," was all Emma could say in reply. With that, Robin steadied himself and attempted to confront the darkness only to be pushed backwards.
"That's not gonna work on this thing," Emma explains.
As Emma talked all Snow and Charming could do was to hold each other, thinking this was going to be another time where they might not survive.
While the Charmings' were internally contemplating about their deaths all Killian could think of was Emma. Since the darkness's escape from the hat the saviour had been eyeing that bloody dagger and now she holds it in her hands.
"Tether it to a person to contain it," It had taken all this time for him to realise the only way to contain the dark beast was to do the unthinkable. He was the next person to unfreeze. Unfortunately, as he took one step he watched his saviour take 5 with the dagger in her right hand. She turned around.
"You figured out how to take the darkness out of me once, do it again...as heroes," she finished.
Hook couldn't let her leave. "Emma please...no, don't do this," was all he could say.
Emma realised at the moment she had to tell him now. "I love you," she breathed. Within that moment everything stopped for Killian, both leaned in and before he knew it he was being pushed aside.
As darkness consumed her all everybody could do was watch. All of a sudden the darkness veered into the night sky, leaving them behind. In a flash of light all evidence of Emma was gone, apart from the dagger left on the street which had engraved her name.