She was blond. It was the first thing he noticed.
Silly of course, that the first fleeting thoughts through his incredible brain upon learning of her existence of his "daughter" were on her hair color. But it was true none the less.
It was silly because, as his daughter, clone, what have you, she was, in part, Time Lord, so she could easily have any shade of hair color in the universe, or no hair at all, for that matter. Time Lords could change every cell in their body—change faces, hair color, teeth, height, weight, mole locations—even if they had children in the human sense of reproduction, there wouldn't have been any resemblance between children and parents, none in the slightest, especially after one or both parties regenerated.
But all this logic couldn't stop his mind from proclaiming that blank statement. She's blond.
The closest thing he would have to a daughter now, and she was blond. And it hurt him.
It hurt a part of his soul he had locked away, oh, so long ago. A part of his being that was guarded beyond all pains and trials he might suffer. A part of what defined him, that he had somewhat lost as another blond women he had known had almost fell into oblivion.
He had had numerous companions, some of which had been blond. It wasn't the color itself; it was the briefest of images that flittered through his mind when he saw her. Images of past daydreams he had dared to imagine while tinkering on something or other while she sat on the jump seat, swinging her legs and singing along with the music blaring from the control room speakers.
He had always known she loved him—had seen it when she looked at him, had heard it when she said she trusted him and had felt it when she looked into Time itself and saved him. He HADN'T known she had been IN love with him, not until Krop Tor, not until she blushed over a mortgage and, sort of, kissed him good luck. He should have been happy, should have shouted his joy at the face of the Beast, showed it that the universe was a beautiful, glorious place that not even his maliciousness could touch.
He should have told her then that he had always loved her. That before she had even said the word "forever", he had selfishly been hoping she would. He had thought that there could be nothing like that between them, though; that he was too old, too scarred, too dangerous. But he had still loved her.
So he had let his heart dream, if not hope. He had dreamt of forever, of her standing beneath orange skies which no longer existed, of their future together, of their children…
And he had asked himself, in mere intellectual interest, of course, whether it would be possible. He was half human, after all. It would have taken a quick blood analysis from both of them to know, but he hadn't wanted to know, hadn't wanted to give up the images of the children they would never have, held in Rose's arms, tucked in bed, playing in the TARDIS pool or visiting some miraculous planet together. Hadn't wanted to give up their smiling faces, little hands, big brown eyes, and corn yellow hair.
And there it was. This young woman who stood before him had cheated him of all that. It wasn't her fault, he knew that on some basic level. But she stood there, grown almost to adulthood, a mockery of the dreams he had had of baby converses, pink bedspreads and visits to Uncle Mickey and Nanny Jackie. And to make it worse, she was blond.
The outrage, the injustice of it all, hit him and, though he knew Martha and Donna were asking him what was going on, though he heard the young woman taunt him saying, "Hello Dad", though he knew the universe was a cruel and wicked place, he felt another small part of his heart grow cold as the pictures of their children were shredded and replaced by this stranger.
A stranger who just happened, he reminded himself, to be blond.