Who tries to fend him off - can't - and she's unconscious, without even a flash of pain.

She wakes bound rather thoroughly, feeling sluggish, like she's been drained of chakra - and she has, she suspects. She'd heard of chakra-draining seals, but to be the victim of one...

"Orochimaru!" she calls through a dry throat. "I know you're there!"

The bells are unbearably loud, harsh and dissonant. 

He walks around into her line of sight.

"Good to see you're still determined. I wonder what sort of person we'll become?"

"Konoha will kill you first!"

"Konoha hasn't managed to kill me in ten long years, child. I doubt they can now."

(Rian doubts that, she knows her sister, knows her sensei, but - )

(The bells are awfully loud.)

He sits down on a chair against the far wall, slouching. He looks nowhere near as imposing as he did in the forest.

"And now... We wait. Shouldn't be long at all."

It's long to Rian.

The bells increase until they deafen her, until all thoughts are lost. She's only vaguely aware of Orochimaru's piercing gaze, of his servants who bring them food and water. 

She's remembering. Recalling something else, something not her.

Eventually the bells die down, and she/he/they open their eyes.

Orochimaru (his/her/their past self? Their predecessor?) hadn't anticipated this, they recall as if through a fog.

Hadn't thought the Uchiha would be strong at all.

(They're not the same people anymore, they realize, and their hearts pick up before they simultaneously take a deep breath, barely centering themselves).

They blink, open their mouths, and the bodies move together. It strikes them both as eerie, but they can't stop, the same thoughts are occurring to them both at the same time. They take stock of their bodies, their eerily unchanged bodies, and both are clumsy at first, new perspectives and new mannerisms and memories telling them that their reach is too long/short, their eyes too far off/ close to the ground, their chakra and skin at once strange and familiar. The Orochimaru-body manages to untie the Rian-body, and the Rian-body stands and stretches, but that's about it as far as different actions go.

Eventually - 

"I'm Rian."

At the same time as their other body says "I'm Orochimaru."

That's a difference.

And they don't remember the impulse to name themselves after the other.

They're separate people, separate bodies.

Now they just need to learn to act like it.

The obvious way to differentiate themselves is to act the way they used to - the way their predecessors/ the previous inhabitants of their bodies did. 

(The now-named Rian hates this, hates existing, remembers being curious and confident about what would happen but also remembers the sheer terror of ceasing to be herself.)

But the old Rian would stop Orochimaru, and while the new Rian, and they think the new Orochimaru, doesn't want to destroy Konoha or kill their friends, it's - 

The obvious way to differentiate themselves is to act the way they used to.

They both scowl, though this body suspects for different reasons. 

"Tell our minions to call off the Invasion. They'll listen to you, you're in his body."

"And waste all this planning? You, too, remember what Konoha did to us."

They do. Fuck but they do, and someone should burn - names flit to the front of their mind - mostly Danzo, but Sarutobi-sensei was complicit in so much.

But - "You know it's not what we want. People will die - it's - death is wrong, no one should die ever. No one should have to be dead!"

(Not their predecessors, either, but it'll be easier to do something about their parents - both sets - and all the dead down the ages of history than that.)

(Some part of them notes that this is a truly fascinating blend of priorities.)

Deep breath. "I'm right. We're right. He - he wasn't, he was blinded by his past and his flawed vision of the future."

"...Danzo has to go."

"I won't argue that."

"I thought you said 'no one has to die'?"

"...When we get around to resurrecting the planet we'll stick him at the bottom of a very dark hole."

"Anyone who dies in the invasion can be brought back. It will make the easiest chance to strike at Danzo and Sarutobi-sensei."