Author's Note: from a prompt at comment_fic on livejournal.

Echo is used to having awkward conversations with the people she lives with. They share a brain, after all, so confrontations are inevitable.

She can tell Caroline regrets her. Even after all they've accomplished together, Caroline thinks of her as a Mephistophilean deal, a mistake made in desperation and the arrogance of youth.

She didn't have to explain how much this cut into her; Caroline could feel exactly how much it hurt. Just like she didn't have to tell her that when she first heard the name "Caroline," she repeated it again and again, waiting for the chant to build up magic, to transmogrify those three syllables into something solid and permanent and real.

Caroline. Beautiful, brave Caroline. True Caroline, who was there before her and would be there after.

Echo thought about her, how Echo came from her, how now she needed Echo to protect both her body and mind so it could one day be born again.

Caroline: her mother, her daughter, her queen, her twin.

For a brief while, she allowed herself to fantasize that Caroline was her self, the secret hidden self deep inside her. That within herself was some hard gem of solid truth and it was three syllables long.

When she found out Caroline was less perfect than she hoped, she stopped feeling guilty for wanting to live longer than five years. But still, she thought of Caroline, said her name as she fell asleep.

And when Echo found out that she was special, that she could never really be purged from Caroline's body no matter what they did, she was relieved. Happy, even, that they would be bonded together, even though she knew Caroline might not like being bound.

Of course Caroline knew all this. She knew everything about Echo now, just as Echo knew everything about her.

So their confrontations, those occasional hints that the sharing of territory held some lingering thorns, were short. Few words were needed, after all.

"You're not what I thought you would be," Echo would say, knowing Caroline understood everything dormant in it.

"I'm not who I thought I would be either," Caroline would say, the accusation clear.

And then they would get back to whatever work needed to be done, their blows drifting to the margins of their consciousness for the sake of necessity or peace.

And Echo would repeat to herself three syllables, reminders of something tangibly true: "I, I, I."