When Hook is referred to as "Hook", it is being told through his mind. When he's referred to as "Killian", we are in Emma's point of view.
Chapter 6: A Fragile Soul
The Fortress contained spacious corridors and, as Emma soon learned, housed more than just Regina and Killian. There were other residents that took refuge there who had once lived in Storybrooke. After she turned, the entirety of the town was transported back to the Enchanted Forest. They divided amongst themselves into the two sides that were now separated by a widening abyss.
There was Robin Hood, the famed hero and thief of Sherwood Forest who stole from the wealthy and gifted the riches to the poor. He was a darling to Regina.
A woman dressed in all black with auburn ringlets grudgingly introduced herself as Zelena, or the Wicked Witch of the West as the people of Oz called her. She seemed proud of the title given to her by those who feared her.
The hair at the nape of Emma's neck bristled when she thought of the inevitable day when the darkness took entire control, and everyone would look at her through eyes blinded by fear and would refer to her as the Dark One. Would she ever get used to the title or revel in knowing that all of the land hated and feared her?
"What's up?" A dull knock sounded at the door of her room which Emma had left open. It was the sound of Killian's hook against the wood.
Emma stared out at the courtyard through her lidded eyes. Sunlight sparked off her lashes. "Nothing much. Shouldn't we be planning to retaliate against Snow?"
"Emma, that is our mother you are speaking of. Do you not recognize that?"
"I know. I know she is my mother but I don't think of her as that anymore. What kind of parent would lock up their own child, their own flesh and blood? Even if she didn't hurt me, didn't torture me, I was left down there in the dungeon. Fed tiny morsels of moldy bread once per day. Locked in iron chains. Just because queen Snow White feared my magic!" Emma's rage boiled in her heart, in her mind. It surged up like a tsunami and engulfed her. "And I don't even have that anymore. What does she have to fear?" Out of words and also out of breath, Emma inhaled and exhaled deeply, her chest rising and falling rapidly. She didn't see it but Killian noticed her trembling figure. Emma crumbled down into the chair she had risen from sometime during her outburst. It creaked under her weight.
Hook moved forward and put his right palm on Emma's hands which were fisted together in her lap. He gripped her hands and the tremor stilled. His left arm hung awkwardly at his side. "Um. I should probably take the hook off." He stood up, unscrewed the hook from its leather base and placed it on the nearby bedside table.
"But now you're not Hook anymore." A slow smile was spreading on Emma's face and Hook couldn't help but notice the difference between this Emma and the one before. They were so different. This one was gentle and seemed almost fragile at times. The original Emma was strong and had forged a concrete wall of a facade that he had had to hack away at with his hook.
"Nah. Killian's good." He crouched down so he was looking up at Emma's golden haloed hair and her pale face that held a soft shy smile. For him. "I just wanted to say that you're different. You're not your mother, whether she is good or bad. You made your own path and I will follow you along that road." Hook grinned. He loved both Emmas, because it was all a part of her. She was a mixture of the two figures he saw but she was also so much more. He had waited a long time to reunite and he would wait again to see the return of the Emma he knew. "Until the end."