The old Rian wouldn't have wanted Sarutobi-sensei dead, but - 

They remember the wars.

And his old teammates would be the logical ones to replace Sarutobi-sensei...

Deep breath. "The full invasion isn't needed. A surgical strike is better - you confront sensei, I corner Danzo."

(They take a mental stock of their reserves. Their yin chakra is much greater, their mental prowess added onto one another, but their yang chakra is unchanged. This will screw with their chakra control, but that should be trivially regained.)

"You'll just get your fool self killed."

"Not if I bring enough of the Edo Tensei with me - we need to alter that technique so it doesn't require a sacrifice."

They open their mouth, then close it and scowl. "That will take - months at least. We don't have that long, our window for the assassination closes soon. We'll use willing sacrifices only."

They consider that, then, reluctantly, "Kimimaro. He's devoted enough. And if we find another sacrifice..."

"You'll be able to have him accompanying you."

Some distant part of them whispers that they're nowhere near prepared enough, that several zombies won't be enough to carry a twelve-year-old through a fight with Danzo, no matter how many memories are crammed into their head.

But neither Rian nor Orochimaru could ever have been accused of being cautious.

They spend the next little while hashing out the specifics of their plans for Konoha - they'll spin it to their Suna 'allies' as cutting off the head of the beast, a less risky proposition than a full-on assault, but still guaranteed to weaken Konoha. They'll each have a sealing team with them, to keep the ANBU and jounin from interfering with either fight. Some of their genin will be sent to distract Team Seven - they're fairly confident Mariko will be able to sense them, and will try to interfere somehow, and they don't want their old team endangered overmuch.

Orochimaru will have the First and Second Hokage with them; Rian will take Kimimaro and the Fourth Kazekage. Hopefully, that will be enough.

Kimimaro volunteers rather easily to be a sacrifice, and they're able to find three more eager sacrifices in time. Harder is finding enough people skilled in sealing to block off Rian's fight with Danzo, but they manage - Orochimaru will be taking the less talented backup, Rian will have the Sound Four, since Rian's is the more vulnerable body. And the more critical one, they're the only one with the sharingan. 

A month after their resonance finished, the third round of the chunin exams is upon them, and their plans for the assassinations slide slowly into place.

Mariko had approached her, shortly into the third stage.

Emi knows about the invasion; she still has contacts here and there from her time in Root. She's not sure why the Third is letting the invasion go - perhaps he thinks Orochimaru having resonated will give him a chance to negotiate.

Emi is not one to talk.

Someone wearing her sister's body is in Konoha, heading for Root headquarters. That's all she needs to know. 

Rian, flanked by the Sound Four and the zombie-Kimimaro (they're waiting until they're closer to bring forth the Kazekage, since he's unlikely to cooperate), senses the attack barely in time, throwing herself out of the way and drawing her chokuto to block the knives driving for her back. 

It's their (the old Rian's?) sister.

They blink, and say, "Emi?"

Throwing the four of the others into a genjutsu is easy enough - one of the guards is a bit trickier - the second attempt takes.

The monster wearing her sister's face is not so easy.

"You don't get to call me by that name."

"I'm still Rian! -Ish! Mostly!" Duck, parry, dodge way out of the way, shit that fire's hot.

"Then why attack Konoha?"

"Okay - I know this looks bad - will you stop - for five seconds - no then - Danzo's evil! - So's Sarutobi-sensei! We're not attacking everyone! Just the people who deserve it!"

"'Deserve it'?" She cuts off her attack, regarding her Rian.

"Danzo has a secret force, Root, he needs to be stopped, and - they don't tell us half of the shit Sarutobi-sensei pulled in the Second and Third Wars. He allowed Orochimaru's experiments as long as they were on enemies!"

"...You certainly sound like Rian."

"It's - I'm not fully her anymore. But I'm not Orochimaru, either. Orochimaru - he thought he'd come out on top. I guess he didn't count on her being so stubborn."

Quiet, then: "You would be. Strong enough." 

Sigh. "Well, come on then, let's get going."

"...What?"

"Danzo helped arrange for the Uchiha Massacre to happen. On one hand, I didn't give a shit. On the other hand, I don't give a shit. Let's kill him."

And she drops the genjutsu on her sister's guards.

?!

(They direct the Sound Four and Kimimaro to stand down. Then they follow their sister, only a bit confused.)

"...I'm not very surprised. At all. He... Still had dealings with Orochimaru, and managed to get a lot of sharingan eyes from somewhere. I figured he just looted their corpses. His bandaged arm is infused with the sharingan eyes, and is infused with the First's cells. He might have other aces up his sleeves, too."

"Then I'll pull out my aces."

"Yours?"