When I woke up I was laying on a pallet in a dark stone room. The air smelled damp and stale and there was water dipping from small stalactites over head. The only light came from a weak candle flickering by my pallet. I was bandaged—and surprisingly—unbound by rope or wire. I quickly found out why as I tried to sit up. Pain like invisible senbon needles skewered me at my wounds. It was quite clear that I wouldn't be able to sit up for days, much less stand or try to run away.
As I fell back on to the crude bed I noticed Itachi sitting in the corner of the room, the picture of health as far as I could see, with no damage at all. He had been toying with me. I might have glared if I had the energy but my vision was fuzzy and his face was obscured in shadow. The effort of staring made me dizzy. I knew that feeling, I wouldn't be able to use my Byakugan anytime soon.
A true born Hyuuga usually doesn't ever experience Byakugan fatigue but it has happened to me, after especially hard fights or missions, ever since I was little. It's because the eyes were forced into me instead of being born in me. Like any organ transplant, it never works as seamlessly as if it were your own, no matter how long you've had for the transplant to integrate with your body some little flaws are inevitable. I don't have any real complaints though, my eyes have served me as well as a native user, they were as good as any and better than most. My field of vision is further and more complete than almost every Hyuuga I knew. My eyes felt especially tender and raw at the moment though, I never had this level of backlash before.
I knew that Itachi was one of the five Akatsuki I wouldn't last two minutes against. The fact that our fight had dragged on should have been a clue I was out classed. I should have run or surrendered instead of insulting him by trying to hide in a genjutsu. It probably made me seem haughty that I thought I could get away from the most renowned genjutsu user on the continent with my pathetic rendition. But now I was a hostage. If they had intel on what Konoha thought of me they might be holding me for a prisoner exchange, but they would find out soon enough I was a missing nin, and then my life would be worthless.
Itachi spoke, "Since you are Anbu you must have seen the files on my clan."
I nodded.
"Then you must understand how I attained Mangekyo."
"You killed the person closest to you," I replied.
He made the slightest of movements and for a moment he looked pained. I almost reached out to touch him but I caught myself just in time.
He shifted a little and continued "What you may not know is that I have only the basic Mangekyo." He paused to let the sentence sink in. It never occurred to me that there were levels of power following Mangekyo, a Sharingan state stronger than what he had arrived at. I shivered.
"If someone took my eyes for themselves," he continued "my Mangekyo would evolve to be stronger in them. Mangekyo grows in power each time it's transferred."
He stepped out of the shadows and I started being able to make out the contours of his face. He had his eyes closed, and there were light scratches around them.
"Someone took your Mangekyo?" But he clearly had it during our fight, so someone had to have taken it afterwards, or maybe he hadn't even had it when he fought me and it had all been an illusion.
His smirk cut off my wild train of thought. "No." He stepped into the light and opened his eyes. I gasped. They weren't his eyes, they were mine. I saw my face reflected in them and knew the coal black eyes I had were his.