A/N: Well, I had to write something. Chapters 356-357 inspired. Spoilers if you haven't read them!
Title: Succession
Kabuto awoke to the white-hot pain that shoot up from his left arm. His voice was dry and rough as he cried out, reaching out to grasp at the wrist with his right hand, holding it tightly. Dark eyes squeezed shut as he turned all of his willpower inwards to face the pain and not let it overcome him. The skin of his left wrist was already dry and smooth—scaled as his master's gleaming white body had been. It would be beautiful, if he could control it.
Like a virus, it ate at him from the inside, as it likely had all of the other bodies that his master had taken in the past. He could have let it devour him completely and be content at the thought that his master would live again, but his body had begun to reject the intrusion all on its own. The only mirror he'd kept in his room had been broken—if he looked into it again he would lose all resolve. His left eye was golden, and bared the violet marks of his master, beckoning him to give in. But no, he could not.
He had to keep this fight up, he had to take control. If he lost himself now, he couldn't be sure that Uchiha Sasuke would pay for his crime. After all, it had been a deal. What right had that arrogant little brat to turn back on his deal—to take his master from him?! And then, he had abandoned Kabuto like a useless tool. He was not useless! He couldn't have taken Kabuto along either, because that would have been asking the knife behind your back to finally sink in. If Sasuke had killed him, it would have been wisest thing. Just how great was this Sasuke, how high and mighty, to think that he could leave behind his most potentially deadly enemy!? He had learned nothing from his time at the Otogakure! After all, Kabuto had always stood right next to the Sannin in all of his devious plans, and helped to mastermind most of them. Kabuto knew everything that Sasuke was planning, everyone he'd gotten to tag along, and everywhere he had been.
Replacing the hand on his left wrist with his knee, he reached to the tableside with a trembling hand. Sweat ran in small rivulets down the sides of his face, making his silver hair stick damply to the sides of his sickly pale cheeks—or was that another side effect? He was looking track. Panting now, he closed his fingers around the syringe. Grabbing the cover in his teeth, he ripped it off and spit it out. He whimpered at the sting of the needle sliding into the skin, no, between the scales of his pinned arm.
"P…please, wait… Orochimaru-sama…" He breathed, feeling the icy liquid entering his veins as he pushed on the plunger. "I-I'll learn to control it… I will… And then I will free you from that wretch's body… he doesn't deserve you…doesn't deserve your power… Nngh..!" Closed his eyes tightly, leaning forward. The arm began to relax as the sedative slowly began to take effect, pain ebbing away to a sweet, sweet throb. He moved his knee to unpin the arm, laying back against the damp sheets and clutching the white-scaled hand to his chest. "Oh…Just wait… I'll give you justice… I will surpass you, and become your successor… I'll ruin Akatsuki, and kill that brat Sasuke… He betrayed us both, after all… And then… You can be free." His eyes fluttered, nearly closing. "Give me… a little more time… I'm almost ready… I know this body, your body aches… it aches to kill Uchiha Sasuke…I'll obey it when I own its power… Promise… That would make you happy, wouldn't it…? We'll kill him together… Orochimaru-sama…" And his eyes closed for the night.