It has forever been thus: a single soul, a single mind divided among two bodies.
When he spills the blood of the humans who seek to conquer all of the earth in their bottomless greed, he knows the fierce joy he experiences is hers as much as his.
And when his heart quickens at the sight of a warrior, wounded yet still unbroken and proud, he knows that, too, is something shared, something not at all shameful or distasteful, for all that he would no more act upon the emotion than she would.
To kiss another's lips would be betrayal - to kiss hers would be ... unwanted. Already, their father the king seeks to separate them, to strengthen Nuala's mind against hers, to make them as two, rather than one. A maiden's place is not on the field of battle; a woman's place is not to lead soldiers.
An army that no longer requires warriors of flesh and blood seems a gift from the gods. It will free him, and so free her. Changes can be made, must be made, to make her his equal fully - but change in a time of war happens but for necessity.
Nonetheless, on the eve of peace, he finds her with a heart as heavy as his own.
"I am unconvinced our father the king is not making a mistake," he tells her. To anyone else, he might have been more outspoken, had he trusted and loved them fully, as he does her.
"The fields and rivers and forests have run red with human blood," she says, neither for him, nor against him. A princess's place is not to argue with the decisions of a king; he knows this.
Her voice - her true voice - is in his heart, whispering her true feelings that are as his, for all that he feels her doubt, her belief that she cannot be right where their father the king might be wrong.
The skin of her hand is warm as he brushes his lips over it, lingering as a lover might.
He feels her spirit within him as he wanders in exile, witnesses the humans quickly forgetting the pact, the treaty they have sworn to, the mercy shown to them by their father the king.
The hearts of the humans are empty still, their memories short. He witnesses the world changing, their kin adapting itself to fit in a world ruled by humans where by all rights it should be the humans adapting, restraining themselves, showing some respect for that which is beyond their understanding.
He watches the forest gods rise up, too late, and doomed to failure without the support of those who yet obey their father the king. The humans come with fire and iron and their ever blinding greed.
Only he - and she through him - feels the way the earth trembles as the last of them falls.
Her voice is in the wind, bidding him to approach, to offer a quicker death than the lingering one offered by the humans, he thinks at first, until his lips are shaping a woman's words of comfort and healing, of sleeping and dreaming.
'One day,' he swears, unheard even by her. 'One day I will see this set right.'