This is a Transformers/Your Lie In April Crossover, hope you enjoy:
Kaori Miyazono was buried in a cemetery in Towa Japan, she had been a carefree and passionate violinist who towards the end of her life, managed to meet and become friends with her hero and the love of the life Kōusei Arima Who she couldn't tell her feelings towards him until a letter that was given to him after death which Kaori stated her lie in April and her love to him.
Her body was well preserved, in fact it was preserved to the point where it was virtually impossible for her corpse to decompose.
2 Years later and a lot of her old friends and family had moved on with their lives, Kōusei and Tsubaki were dating after Kōusei somehow managed to get over Kaori, Watari has stopped being a playboy and settled down with Keiko and Kaoris parents still ran their bakery which they still missed Kaori to the point where they stopped making Caneles, However they knew in their eyes that Kaori wasn't coming back so they decided to try and move on.
However after 2 years, Kaori was about to be brought back, but under different circumstances.
Shockwave was doing an experiment where he wanted to cyberform a organic being in order to create a new powerful bot for the Decepticon war machine, in order for it to work, he went forward in time to Earth in the modern day in order for the organic being to be advanced than just some caveman.
Shockwave decided a well preserved dead person would be the most useful option as if it's brain was still there, it can be useful, also dead people weren't going to resist the experiment anyway.
Shockwave scanned the Towa Cemetery and found a match for his experiment, Kaori Miyazono, Shockwave managed to remove the mud using a air blower and then opened the casket, taking Kaori Miyazono through a portal and into his lab on cybertron millions of years prior and got to work
First, her heart was removed as the disease that killed her affected her heart the most and Shockwave replaced it with a freshly created spark which he used to power her brain, keeping her memories intact, However hidden away using programming which was to control this new being.
Then she was put in the cyberform machine and it merged her body with robotics (mainly muscles were replaced by robotic parts, but her whole body remained intact) and then a Robot body suit was created, Shockwave using a database collection of Kaori decided to make the bot music related which was to make this new Kaori bot not only effective, but obedient.
The Robot Body suit would also act as a life support system, Kaori would survive an unlimited amount of time without the helmet, she wouldn't without the rest of the suit due to the robotics and lack of heart.
After the Robot body suit was fitted onto Kaori, Shockwave then began working on a helmet, this helmet would have a red visor and a robotic voice changer which changed Kaoris voice into a more robotic voice.
Afterwards the helmet was fitted and then the body was painted blue
Afterwards he gathered some earth based cassettes and gave each one a spark before slotting it into this new bots chest
Afterwards Shockwave activated the spark
"Where Am I, Why do I sound like this Who am I" said The bot
"I'm Shockwave and your in my lab, you sound like that because of a robotic voice changer and from now on you will be referred to as Soundwave and you are a Decepticon" said Shockwave