The first time Hook sees her since she became the Dark One, he is in awe. He never expected the Dark One to be so… light.
Her hair, her skin, everything is starkly white.
Her eyes though, those beautiful eyes that shone with fire just a few days before, are now empty. He has to turn away from the soulless nothingness.
He absentmindedly reaches into his jacket pocket to run his finger over name etched into the dagger he safely keeps by his heart. Emma Swan. This woman, this thing, standing before him is not his Swan. His Swan is essentially trapped in the cool steel resting against his chest.
He dusts his finger over her name once more before lifting his eyes once again to his former love.
Emma smirks at him. "What's the matter? You can't handle the new me? You prefer the old Emma? The Savior? The pushover who put every other loser in this town before herself?" Emma sneers. "Well, you better get used to it because this is the new Emma. The spineless fool is gone. I'm the Dark One now." At the conclusion her rant, Emma's eyes are even blacker if possible.
Hook is appalled by the way Dark One spoke of Emma. "Of course I prefer the old you!" He shouts. "I changed for you. I know what it feels like to be a villain. I understand the appeal, but bloody hell, Emma! You have a family, people who love you. Henry needs his mom, and Neal needs his sister. Your parents, your parents miss you. They aren't taking this well at all."
He sighs and stares straight into those blank orbs. "And I'm suffering more than anyone. Your family, they have each other to get them through this. I don't have anyone. I mean, they've tried to welcome me, but I feel like I'm intruding. You're my family, Swan, and I know this won't mean much, but I love you. I told you before that you were my happy ending. I still believe that with all of my heart. I'm going to get my Swan back and destroy this infernal dagger. I've been chasing the Dark One for years, so don't think for a second that I'm going to stop now."
Killian's eyes shone with unshed tears, but through his blurred vision he glimpsed something. Emma's eyes transformed. They grew wide and shone with the love he knew she felt for him. It was only for a second, but Killian saw it. His Emma was in there somewhere, and he was determined to get her back.
Emma steeled her expression after Killian's speech, and with a puff of smoke, she was gone.
Killian pulled the dagger out of his jacket and whispered, "I will get you back, love. I swear it."
The next time Hook sees Emma, he walks straight up to her. He promises once again to never stop fighting for her. He tells her how much he loves her. He knows it won't change anything, but that flash of love in her eyes makes it worth it.