He'd discovered his magic quickly when he'd wanted to be as far from Swan as he could and had suddenly found himself aboard the Jolly. He didn't see anything, but there was a quiet voice in his mind whispering reassurances. He almost thought it sounded like Emma, before she was the Dark One - a Dark One - but he ignored the whisper and paced the deck of his beloved ship. His magic was volatile, itching under his skin, making the little hairs stand on end. It was begging to be used, so he pushed his hand forward and the sails billowed with wind, but the ship was restrained from moving by the anchors and ties. His newfound power gave him no joy, no wonder, as it had when Emma had embraced hers. It was ugly and dark and something he would have rather died than be burdened with. He wasn't strong enough to fight the temptations the darkness offered.
The whisper insisted it could help. It sounded so like Emma.
How could he refuse that blissful whisper?
He gave in to the words that said all would be alright, everything would work out if he just succumbed.
Just a day later, Hook was about to deal the final blow to Rumplestiltskin when he was suddenly transported in a cloud of gray smoke to the house he'd chosen for his Swan, devoid of Excalibur.
He whirled around and saw her standing by the telescope she'd set up to see the ocean. Her appearance jarred him for a moment. She no longer wore the tight black pants, the jacket, or the severe white bun; she had returned to her comfortable jeans and red leather jacket, golden hair flowing freely down her back once more.
His surprise was momentary, however. His anger at her quickly took over and he attacked.
Grabbing her by the throat, he forcefully pushed her head into the table behind her, bending her over backwards.
"You!" he growled. "How dare you! You dare steal me away from my own ship? From delivering a punishment centuries overedue? How dare you even think you can control me just because you cursed me!"
Take her power for yourself, the voice in his head whispered. Take her power and show her why she should have let you die. You can do it, I'm right beside you. Show her why she's wrong.
His grip on her throat tightened and Emma could feel his power stirring. She didn't fight back. "Killian," she choked out. "Whatever the...darkness is saying...don't listen to it. Back in Ca-Camelot you helped - me banish the visions - the voices. Helped me fight. Let me do the sssssame for you."
"Why?" he yelled. "Why should I trust you now?" His grip tightened as he lifted her back up and held her face level with his, her toes barely scraping the hardwood floor. "Tell me why I should even continue to let you speak to me when I would rather never hear from you again."
He dropped her to her feet. She didn't bother coughing; while he had constricted her airway, he couldn't physically hurt her.
"You're angry," she said. "I get that. I went against your wishes - your dying wishes - and turned you into the very thing you'd hunted for centuries, the very thing you abhorred the most. Believe me, I get that you're angry at me. Hell, I hate myself for doing it, but I didn't have a choice!"
Hook interrupted her, gesturing with his hand. "You bloody well did have a choice! I didn't want this! You could have let me go and gotten rid of the darkness completely!"
"NO!" she yelled. "No I couldn't! I could not let you go. No matter what happened, if you had died, Emma Swan would have, too. The Darkness would have taken over completely and I would not be me anymore.
"Don't you see?" she whispered, and it sounded so much like the whisper in his mind that he had to strain to make sure it was real. "I've been trying to tell you, all of you, this whole time. I'm still me. I can fight the darkness. Those visions and whispers, I can banish them and think for myself. I can do that because I'm fighting for you, for our future. I love you, Killian. I cursed you to save your life because I can't live without you anymore. Let me help you fight the darkness."
Hook clenched his teeth, the muscles in his jaw jumping. "It's not that easy, love," he spat. "Darkness has been an all-too-familiar part of my life. What helped me before was being a better man for you." He barked a harsh laugh. "But you, Swan. You've fallen so far. How can I possibly trust you to help me when you're the one who not only cursed me in the first place, but decided that the best way to rid us of our curse - which you took my memories of, by the way - was to take all of the darkness and put it into Zelena and kill her with Excalibur? How can I possibly trust you when you are so far away from the Emma Swan I fell in love with that you would burden yet another person with this bloody curse and then kill them for it?"
"Because saving you was my one selfish act!"
Silence followed the outburst.
Continuing in her whisper, "Since I came to this town and became the Savior, I have not been able to do anything without thinking of the consequences. I haven't had the chance to do anything for myself. I haven't had anything just because I wanted it. The only day off I've had from being the Savior was our one date. Saving you was my selfish act. Because I wanted it and I could make it happen. I had the power to save you so I did. Regina made me save Robin. Mary Margaret split her heart with David so he could live. This is no different. Neither of them would be the same if Robin or David had died. I wouldn't be the same if I'd let you die. If I'm your happy ending, then you're mine, and I will fight...as hard as I possibly can to keep that - you - alive. You are it for me."
She doesn't love you, the voice in his mind said. Listen to her - she was selfish. She wants to keep you all for herself - wants your power all for herself. She just wants to control you. Don't listen to her. You don't need her help. That's what I'm here for.
Hook felt the magic tingle through him as the whisper went on, felt it rush to his fingers like blood prickling after it fell asleep. It was almost painful in its intensity.
Show her you don't need her help. Hurt her like she hurt you. Take her power away from her and make her suffer, make her miserable. I promise you'll feel better when it's over.
Hook's eyes glinted steel in the pale light filtered through sheer curtains. "I notice you still didn't explain why Zelena had to die. It's not like the Swan I know to advocate death as a solution. The Emma Swan I know didn't even want the bloody crocodile to pay for his crimes. No, whatever your "reasoning," you're not the Emma Swan I fell in love with. You're the Dark One, just as I am. Just as you made us."
He shoved his hand into her chest and grabbed her heart, but didn't pull. Instead, he absorbed all of the darkness from her into himself. His disheveled appearance worsened, the black around his eyes deepened. The whisper in his head changed to a high-pitched, eery cackle. Hook's own heart stuttered at the sound and his mind cleared enough to see what he was doing: Holding his Love's heart in his hand and draining her.
He could feel the power swirling through him more intensely than before, but he focused on the woman before him and blocked it out as best he could for now.
Emma slumped into him and passed out; he lay her on the floor and removed his hand from her chest, then he summoned Excalibur to him. Emma's name was no longer on the blade, just his.
The harsh cackle sounded again and an image of the Crocodile flashed before his eyes, flickering between him and the Dark Swan before settling on the Crocodile for good.
"Well done, Captain. You have all the power of the Darkness for yourself. What are you going to do now?"
Killian's eyes widened. Full recognition and awareness of what he'd done hit him and he crouched down to check on Emma. Her pulse was strong and she was still breathing. She'd be fine. He let out a sigh of relief.
There was only one way to irrevocably rid the world and himself of the Darkness now.
He disappeared in a cloud of black smoke, reappearing at the doorway of Gold's shop.
"Alright, crocodile!" he exclaimed, tossing the legendary blade onto the sales counter. "Kill me. I've absorbed all of the Dark power from Emma into myself. If you strike me down with Excalibur now, all of your problems are solved. I die and the Darkness dies with me."
Hook held out his arm and twisted his wrist. Belle fell to the ground, choking.
"If you don't do it soon, I will lose what little control I have and I will kill her, and then you."
Rumplestiltskin faltered at the sight of his love on the floor, but quickly poised the blade and swung.
For a moment he thought he'd missed, as there wasn't a scratch on the pirate. But then the darkness seeped out of Hook from the slice he'd made. Hook fell to his knees and the darkness sank into the floor like water into dry soil.
For a moment, Killian's eyes shone bright and a corner of his mouth almost turned up.
Then he fell face-first to the floor and didn't move.
Belle, once more able to breathe, made her way over and turned him, searching for a pulse that wasn't there.
Emma burst through the shop door, then, out of breath for the first time in months. She was about to ask if they'd seen Killian when she saw him. He looked serene, peaceful. So unlike he had mere minutes before.
"NO!" she sobbed as she fell to his side. "Dammit, Killian! Why?! Why couldn't you just let me help you? My way made more sense. Zelena doesn't belong here, of course it had to be her. Zelena deserves to die, not you!" Emma held her pirate close and let her tears fall into his dark hair unchecked.
Belle had called Mary Margaret, who said she'd tell Regina. They appeared in a puff of purple smoke minutes later.
Mary Margaret was the first to speak, though hesitantly. "Emma?" It was the first time in weeks that she'd seen her daugher look...normal. "Emma, honey, are you...are you you again?"
"Killian..." she sniffed, still rocking his body. "Back in Camelot, Killian was scratched by Excalibur. The blade was cursed so any wound couldn't heal, even magically. I tethered Killian to the broken Excalibur and made him into another Dark One."
Everyone but Rumplestiltskin gasped in shock. Emma continued.
"He begged me not to - you all did. He would rather have died than take on the curse. But I couldn't let him die and it was the only thing I could do to save him. I thought we could fight it together, that we could beat the darkness together. But he hated me for it." She sobbed again, harder. Mary Margaret crouched beside her and put her arms around her daughter.
"He took all of the darkness from me into himself and Gold cut him down with Excalibur. The Dark One is gone and so is Killian."
A/N: Thank you to my lovely beta Jenny (aka wayward-walkerkilling-pirate on tumblr) for helping me bounce ideas back and forth before we decided not to really change anything. Title comes from Chevelle's song of the same name.