Meanwhile back in the 'void'
Everything was dark then suddenly a sound of a bookshelf falling over thundered out as an infinite amount of games, movies, books, and food fell for the next 3 hours.
"Damn it, who the hell turned off the lights in here! I can't see for shit... Ugh maybe I can leave this mess for the next god to clean up not like anyone is supposed to be... in this... personal... heaven..... wait no that is the next room over. Alright let's see what the problem is here then."
After some fumbling in the dark the void suddenly light up to show an empty little heaven filled with as much food as one could eat and more entertainment to last past the end of time. In the mess of everything that fell over stood a man in a white suit with a clipboard as he messed with a fusebox yelling "Yes there we go all systems back on now let's see if the admin log emergency power can tell me what happened. Wasn't someone supposed to be here after all?"
The man started to read a log that basically showed a slow decent into madness as with the power out prevented his heavily body from being constructed to enjoy his little slice of paradise. Not that he could with everything turn off either. "Okay now this is raising alarm bells since he certainly isn't here." He kept scrolling until the most recent logs to suddenly pale and break out in a cold sweat.
"Ah it can't be that bad, just a system got past the offline defenses and alarms... At least it isn't a rouge or faulty system... please One Above All let that not be the case." After some more time digging and panicking he finally fell on the heavenly bed giving up. "It is both... I can kiss my vacation goodbye... unless... unless I can cover this up."
He began destroying evidence left and right as he erased this one mortals existence from the history books and logs. "It's not like a god will find him, the system may be rouge but it is faulty. The guy will be lucky to be half as strong his first life forget being stronger. He was a nobody that no one will remember missing from the fabric of realities."
Back with our protagonist whose own original life was becoming blurry itself was fighting in his subconscious to not be drowned out by the other lives and personalities. The struggle was a difficult one but in the end the only thing he was clinging onto was a fear of nonexistence like his time in the void that overpowered roxas own fear of the same despite being an existence that was never supposed to exist in the first place.
After a long grueling time he finally feels his head clear up and settle down as a synthetic voice calls out [synchronization complete. System congratulates host on not being overwhelmed by the other personalities. Note all memories are for the host to access on your own accord and time. All powers are at base minimum level due to vessels current state and lack of training. Have fun!]
'Well I guess that is all I'm gonna get' he thought before creaking open his eyes to find himself no longer in the vat but chained to a surgical table with a collar on his neck. 'I see I still hate shit close to my neck' he thought trying to move his hands up to his throat and loosen or remove the collar only to rattle his restraints.
"Ahh, I see you are awake now. I've already checked your body and I can certainly say I have outdone myself this time. Hehehe you will be my ultimate weapon with all that pent up potential in you. Unfortunately I'll have to tame you to be more obedient hound, or should I say feline haha." The first thing I do is try to retort with a witty 'what the fuck are you talking about' before I find a nice shock sent through the collar. After a few moments I come back down from the pain and try to focus more on my general situation including the things I never had before. For example a pair of cat ears and a tail...
That was not something I was expecting. Noticing my confusion the mad scientist leans over me with a disgustingly delighted smile and finally giving me a clear look at him. "Allow me to explain a little for you. I don't much care for things that talk back to me so I decided to completely get rid of your ability to talk while I'm training you. I'm sure you have heard of Pavlov's dog so you can imagine your future if you choose to try and talk at all or attack me." Looking at the man I finally put together where I have seen him before and I realize 'Isn't this Izuku's quirk doctor?'
Seemingly uncaring of my recognition of him he goes on to explain. "I also made your body to be the strongest there is. Well in the future, I'll need you to be under my control before I allow you to have strength enough to try and resist me. I gave you multiple quirks even. You are a lucky duckling since some people don't even get one! I should thank all for one for the help in creating you, his input was invaluable."
Ignoring his ramblings I look around myself and take note of a few things. First there is a mirror to my left that allows me to see myself in a set of scrubs, second I look like itachi uchiha with a natural set of cat ears, third was the fact he said all for one when I started tuning him out. 'Holy shit I'm a sentient nomu'
Finishing my looking around I don't notice much as the room is pretty spartan save the table, mirror, and medical equipment. Speaking of the doctor steps back as he continues to drone on about his own brilliance and the failure of others to see it or something like that so I slip a scalpel into the palm of my hand using itachi's memories as a guide. Unfortunately I didn't gain his genius intellect nor Revan's so I only have myself to count on. 'I'm fucked' Okay I don't see myself being that reliable but I can do this or I won't be seeing freedom anytime soon.
Finishing his rant he returns to me and starts undoing the restraints on my legs then goes up towards my hands "Don't forget that collar will hurt you every time you try to raise your hand against me" before letting me 'free' and I think back to him 'at least this damn thing can't read my mind and prevent me from scheming... right?'
I sit up slowly and run my wrist as he continues to explain pulling out a small yellow remote giving me a short warning zap. "I also have the remote to shock you anytime I wish and I shall be doing so randomly. I also can end your life but I think neither of us want that. Now follow me to your cell or bedroom whatever you want to call it. You will sleep there then I will start some training for you tomorrow. I need to make sure you are in top shape, can't have a dull scalpel after all."
I follow him as we reach a dull grey cell that is as appealing as a jail cell. 'Wait it actually is a jail cell' I think as I look at the room as he slams the door shut and locks it behind me taking off to leave me with my thoughts and half baked plans to escape. I toss myself on the bed and rub my eyes lost in my own little world. 'I guess I should be patient and think this through. Sigh this may take awhile'