While travelling with Emma, Killian realises he desperately endeavours to replenish whatever she loses.
It helps soothe his own pain, knowing he can help give Emma back individuals in a way he never had a chance to do so for himself. Killian would never admit it, but it warms his heart to see his actions leading to glimmers of hope in Emma's eyes. Once, a long time ago, the same hope would have been etched in his own expression — until it was torn away from him so cruelly.
Now, Killian wishes more than anything that the same doesn't happen to Emma. He wishes it more than the fulfilment of his revenge. Killian always prided himself on striving for his own ambitions, however ever since Emma spiralled so unpredictably into his life, he finds himself second-guessing how much his choices are actually about him.
Nevertheless, with elevating selflessness comes acquainting sacrifices. His shift into a more tender demeanour does not go unnoticed by those who are close to Emma, notably her parents. Killian never misses the suspicious glances from Snow, nor the accusatory tone in Charming's voice as he addresses him sternly.
Killian tries to not let Charming's cutting words slice through his defence, especially the venomous disdain when he states that a pirate is all Killian will ever be. Such a comment churns bitterness in his throat as Killian thinks back to the days where a pirate wasn't all he was, but stops before he can remember why he became a pirate in the first place.
Despite the bitterness, Killian does not hold Charming's words against him whatsoever. In fact, he understands the protective sentiment and continues to work for Charming's approval. Yet such approval is not in Killian's mind when he saves Charming in a method reminiscent of his own brother. All Killian thinks about is Emma's despair if she were to lose her father — pictures how the sadness would well in her eyes like a mounting dam about to break — and decides there was never a choice. Not anymore.
Killian recognises he is at a point where he will inherently position Emma in front of himself. He can't figure out whether it is a curse or a blessing. It is more of a blessing for Emma, Killian supposes, and that's all that matters in the end. Or at least, that's what Killian tells himself.
It stays this way even when Pan resurges, albeit unwelcome, into his world. The pleasantry of the kiss Killian shared with Emma becomes clouded as Pan snidely reveals Neal's existence. He is calculatingly aware of the ramifications such a name presently has on Killian and Pan doesn't bother to hide the complacent smirk gracing on his lips.
But what Pan cannot grasp, in spite of all his duplicitous cunning, is Killian's love for Emma. The manner of this love is not selfish as Pan suspects, instead it has cultivated rapidly into an all-consuming nature which blinds Killian's sight from anything other than Emma.
As Pan leaves, Killian imagines Emma running towards her son and Neal, her arms open for an embrace Killian could never hope to receive. He can visualise how her smile would spread happiness to every crevice of her face, sunshine spilling from her skin. She would be beautiful.
Killian registers why he buried his past behind him for so long. It is because remembering is much more painful — remembering that indeed, he is not a true pirate, could never be a true pirate. There is not enough cruelty in his veins anymore to convince him of a selfish resolve which would hide this secret from Emma.
He remains the vulnerable human being whose brother and love died before him, the first stranded in Neverland and the other's heart crushed in his wake. It is a ridiculous thing, to have fallen in love when Killian knows loss so well that he can smell it behind every hopeful veneer, awaiting his disillusionment. For the first time, Killian despises that he is not heartless enough to shield him from the inevitable heartbreak.
Regardless, Killian admits a more damning truth seconds later: he would stand unprotected as many times necessary for Emma.