Fritz Krohner and his twin brother Mortiz were born the 10th of October 1935 in Bremen, and their parents were Jewish. He also had a older sister that was 20 years old at the time, Julchen, and on that day she took the two newborns and brought them with her in St. Louis, USA.
She had a difficult life trying to raise two kids and at the same time working as an assistant nurse trying to get a promotion in surgery. Fritz always had a special interest in the art of medicine as well, while Mortiz had a better inclination in learning languages, and by age of 12 both the kids spoke a various range.
When Fritz was 13 years old he came out to Julchen, and she helped him in his transition, giving him a hysterectomia when Fritz was 16 years old. At the same time, Mortiz decided that he wanted to get back at his roots so he was sent to a private school in Germany, but he decided that school was too strict for him, so he ran away, living on the streets for some time, disappearing from Fritz and Julchen lives, until when he finally found a job he could write back to his siblings. He then decided to go back to the USA and to live in Chicago as a Adult Intertainer.
Fritz went to an all male medical school, he graduated with excellent grades and when he was about 20 years old he started to work/study for a hospital, and there he met George Smith, a fellow doctor a couple years older than him that was extremely jelous of Fritz's work and intelligence, so he decided to hire a private eye to spy on him.
Dr. George Smith and the beginning of the end
The private eye of course discovered Fritz's secret, so one night Dr. Smith went to his house to blackmail him. Things may or may not have happened, and Fritz killed him in self defence. This brought Julchen (that throrough the years became a really important surgeon and opened her own private clinit in Iowa) to mess up a little with police and Jury and press, Making his brother attend to a Female Penal institution, where he was supposed to stay for only one year, but since he was attacked by some inmates and he killed them, his punishment was raised up to 5 years.
He spent those years in somewhat tranquility, nobody tried to mess with him and at the same time he managed to get in touch with some gang memember part of the mafia.
After the sentence
When he ended his sentence, Julchen brought him in her facility to work with her, but he at the same time started to live a double life between working a little for the mafia and experimenting on human guinea pigs, until the day where he lost his medical license because he tried to heal a stomach with a blowtorch.
This was the last straw for Julchen who sent him away and cut his name from her will.
So Fritz went back to Sant Louis and started a new career as a tutor for medical college kids by day, mad experimenters by afternoon and disposer of corpses by night.
Fritz is the main characters of a book I am writing, a couple of roleplays with my partner and basically the "story" only starts from this point.
The TF2 version is him receiving a letter to work with BLUs, in my book he meets a Private Eye and they start a life of chasing, and the choices are multiple and different.