Hope
It was the one thing he'd had left, and the one thing her death had taken away.
He'd always known his life wasn't going the way he wanted it to and that he had no choice - being William Adama's eldest son he had to follow his father's footsteps, but somehow she'd always given him hope that anything was possible. She was Starbuck, and if that word wasn't synonymous for 'anything goes' he didn't know what was.
But though they'd had their issues, their fights, their times of hatred, he'd never stopped thinking of her as his beacon of hope. His reason to keep on fighting.
Till now.
She was gone. Gone forever and she wouldn't come back again. Not this time.
Now he was left with a gaping hole where she used to be, a hole he could only fill with the same blackness and swirling death that had claimed her.
Hope had no place here anymore.