Gunther Milch is an escapee, con-artist, and thief who helped Dr Tenma break out of prison when he was arrested on false charges.
He can be described as quite the eccentric, manipulative, selfish, and pragmatic individual. Often showing little concern for others his main focus seems to be on his own survival. However, he does take interest in others mainly being Dr. Tenma, offering to help him escape prison noting his gloomy appearance. He often wears a smile on his face and has droopy eyes and high eyebrows, this look is that of a man who doesn't really care. He also displays signs of detachment, never much caring for his situation possibly due to his accomplishments which he puts above all else using them to put others down.He takes a very sarcastic approach to his interactions with others, often taunting and teasing them for their shortcomings, including Tenma when he berates him for supposedly having killed quite a few people to his knowledge, whilst mentioning he himself has never killed anyone on the job.
His methods are simple, he himself being a good actor is able to escape the same way he steals, by feigning illness. He easily fools the prison guards but not Tenma showing how limited he is in his abilities to fool only the common man and not those with a keener eye for fraudulence. Whenever he attempts theft it's either him or his brother Gustav who wander onto the road and collapse causing the drivers to pull over and try and help them as best they can, after swerving past to avoid running them over. This is when the plan springs into action and they hold the men at gunpoint and steal all the valuables. His brother Gustav does the dirty work in getting him out of prison by doing the same thing, however he is younger and not as good as his older brother Gunther given his timing only allows cars to speed past him instead of crashing and forcing them out to help him.
His attitude towards being in prison is that it sucks the life out of a person and that he isn't too fond of cramped places. This could also translate to how he views many things such as his life itself in refusing to live an ornate and dull life even dreaming of one day travelling to Tunisia, a place he's admired from a young age.
He also enjoys a show called "Detective Forster" which he asked his lawyer to urge his relatives in recording it so he could watch it when he got out. It reruns Tuesday mornings at Ten, implying he's memorized the dates because he loves the show so much.
At a young age his parents would often stuff him in a coin locker before heading off to work and would leave him there in what he describes as an eerie darkness as he'd eagerly await their return. They always toted the premise of travelling to Tunisia with him if work went well for them. He waited for Three days, once more eagerly awaiting for his parents to return only to find that they never returned, he himself always assumed they'd left for Tunisia without him. This is his motivation for stealing is to one day make enough in stolen profits so that he may travel there, either to meet his parents or live his days out peacefully in content.
He also has a brother named Gustav, who helped him in stealing and along with his girlfriend appear to be users. Gustav has an affectionate and concerned girlfriend named Helene who often rides along and seems to care for him dearly even vowing to stop doing drugs if he doesn't kill anyone on the mission as she doesn't want their children have murderers for parents. They both seem to love each other dearly and it's unknown if Gunther himself has a romantic partner but it's hinted that he doesn't due to saying at the end him and Tenma would have a lot of girls to enjoy in Tunisia.
Prior to meeting Dr Tenma he had been incarcerated in 1988 for the robbery of an armored vehicle from the Bavarian BASF Bank, a whole 8 years prior to when the series main story begins in 1996. He was placed in Badenburg Prison but escaped in '91 by spending half a year cutting through the iron bars of his cell window with a nail sharpening into a file. Three days later he was caught and sent to Kreiner Prison but escape through the drainage pipe in 1993 with his prison uniform being found 3 days later on a nearby riverbank, covered in excrement. He was arrested once more for attempted robbery of a Maximilian & Co. paycheck delivery truck. He was sent to Ingeburg prison where he escaped through a shower stall in '97 after spending a year and a half digging a hole in it with a spoon.
He works under an unknown "Boss" who spearheads the operations, and even sent a lawyer to visit him whilst incarcerated.
In the main series he meets our hero Tenma in prison when he has been wrongly convicted of Johan's crimes. Initially seeing him as he's cuffed and walked down the hallway to his cell their first formal meeting happens when he fakes being ill to get close to the doctor. Tenma appears to him as a deeply disillusioned man and one he feels sorry for possibly due to sharing the hatred of being stuck in tight areas, he offers Tenma a choice being to go with him when he inevitably escapes or stay behind, an offer he is unsure of at first. Tenma proceeds to go through with the decision after learning Roberto is alive, a man he'd thought he'd killed, and was going to end the life of his ex-fiance Eva Heinemann. With this Tenma confesses to the crimes he did not commit to ensure he is transported along with Gunther, meanwhile Gunther talks with his lawyer and requests his relatives records the show "Detective Forster" so that he can watch it upon his escape.
Eventually the two are transported by the guards whilst Helene and Gustav are waiting for the truck to pass, so they can hold em up. Before hand his brother is sidetracked whilst talking to his girlfriend about getting married and having lots of children and doesn't see the truck coming. When Gustav is hit and the guards get out Tenma tells them he can help the man but it's all a ruse when he takes the gun he was carrying and turns it on the guards threatening them. Tenma, Gunther, Helene, and the injured Gustav all get into the car and drive away but Tenma being a man who values every humans life demands they pull over and have Gustav taken to the hospital even threatening the abrasive Gunther with a gun. The two go to the hospital and their fate afterwards is not revealed.
Gunther is last seen with Tenma as he is thanked for helping his escape, Gunther tells Tenma he is better off sticking with him as the two would be safer this way. Tenma shocks him by explaining his reasoning to escape being to save a woman's life. "A woman? You mean to tell me that's why you escaped?" surprised that the Doctor could be so selfless not only for his brother but to save a woman's life, even unmoved by his offer of the beautiful woman he'd find with him in Tunisia. He then inquires if Tenma ever truly killed anyone as his kind heart seems to contradict the accusations leveled against him, and Tenma admits he shot one man but never truly killed him and he says as far he's concerned Tenma is an innocent man, but that Tenma is now a real fugitive from here on. Tenma then departs as Gunther says to the fugitive, "Let's meet up in Tunisia one day, fugitive to fugitive, It's a great place!" being facetious. His status there on is unknown but we can only hope he's in Tunisia now living his life in peace.
"I first became aware of myself in a coin locker, in that eerie darkness..."
"I've never killed anyone, unlike you"
"Staying in a place like this will suck the life out of you, I hate cramped places the most!"
"The plan... Failed, Dr Tenma"
"Doctor, you haven't really killed anyone have you?"
- The prisons he was sent to do not exist in the real world, but they all seemed to have their names based on real people.