In Monster, Tenma is brought to the sick ward because he had collapsed from not eating. The viewer's immediate reaction is exasperated, because Tenma alwaysfails to eat, but in this case it was intentional, as it allowed him to speak to the man whose help he needed to break out of prison. - insofar
The first ending credits song is, obviously, about Tenma's idealistic philosophy, although it's deliberately creepy and eerie, like the show. The second ending credits song bothered me, because it was bright and cheery in both lyrics and feel, which didn't make any sort of sense, until I hit episode 70 and realised it's about Johan's philosophy. It's an exact reversal of the Soundtrack Dissonance of the first credits song! Brilliant! - randomfanboy
It's small, but when I first watched the last episode, I didn't understand why Lunge/Runge/however you want to spell it put a beer on Grimmer's grave. Then it hit me: they had promised each other to go get some nice cold beer after everything was over. - Toa Novu
In Another Monster, it is revealed that Nina celebrates her birthday in May. This doesn't seem that special at first, but depending on whether or not this is the real month of her birthday (and by extension, Johan's) and what day in May their birthday falls on, this may or may not be Fridge Brilliance: If the twins were born between May 21 and May 31, then their Zodiac sign would be Gemini, aka The Twins.
This one is a bit of Fridge Horror: Mr. Grimmer admits as an jocular aside to a group of orphan boys about his bed-wetting issues as a child. It isn't until later that we learn he actually was a product of Kinderheim 511.
After finding out Johan specifically wants Tenma left alive, I was confused as Johan never seemed to do anything to ensure Tenma's survival. Then I remembered Tenma's conversation with Roberto. At no point are we ever given even a rough idea of how many followers Johan has. There could always have been someone there to make sure Tenma lives.
My girlfriend (who's a major in Nursery) explained to me in a casual talk that there's a theory saying that neurosurgeons may have tendencies to become assassins and then they suppress this tendency by becoming neurosurgeons. I didn't check if this is true, and something may be Lost in Translation (because I use English as a second language), but, if this is true, this CHANGES THE MEANING OF THE ENTIRE SERIES! - Not JM Keynes.
Psychoanalysis by Freud supports this idea.
And sometimes a cigar is just a cigar. Tenma isn't the most realistic surgeon. In fact, surgeon is #5 on a list of careers that attract people with psychopathic traits, and Tenma is definitely no psychopath. (That would explain Heinemann and the other surgeons' callous attitudes though...) He even admits that he gets nervous while performing surgery, so he's not really comfortable with the idea of cutting people up. It's also possible that he wasn't even planning to be a surgeon initially, since in Another Monster it's revealed that he went to study under Heinemann due to an article on Alzheimer's, which would fall under neurology instead. This does hold interesting implications for Franz Bonaparta, however, since he was also a neurosurgeon in addition to being a psychiatrist and a children's book author.
This is both Fridge Brilliance and minor Fridge Horror: Remember Tenma's little flashback after the Turkish man's wife confronted him? While it may not seem like an important point, Dr. Oppenheimer didn't directly tell Tenma that he was switched. He simply said that the Turkish man's operation wasn't his operation. Tenma could have simply taken that as there being a mix-up of some sort. (Note that he was just getting done putting on his scrubs. Later, when we see him looking at Johan's x-ray, he already has his scrubs on. So with the Turkish man, it was likely that he had just come in.) This casts Tenma's Just Following Orders comment to Eva in a different light: He wasn't responsible if it was the director's mistake. It was only when Eva replied that not all lives are created equal that Tenma started to catch on to what really happened. If this is what happened, that means that Heinemann was intentionally deceiving Tenma to get him to comply. When the deception failed due to word getting out that the Turkish man did come in first, Heinemann had to use other means to get Tenma to do his bidding, such as appealing to his desire to do research. This leads to another question, however: Just what else did Heinemann do to deceive people? We know he never told the truth about the paper that inspired Tenma being ghostwritten. There's no telling what else he could have done.
Nina's romantic emails turning out to have been sent by Johan.
Just what exactly was it that Franz Bonaparta wanted to achieve? Did he really try to create what Johan became? And if so, WHY because there is no way a creature like Johan can be controlled once he gets out in the world. Could it be it only was an experiment for the heck of it?
Johan's eerie imitation of everyone's favourite bedtime storybook, The Monster Without a Name. The monster goes through the village in search of a name, taking on the names of various people willing to "take him in" (literally) before killing them. Johan does exactly the same with his string of foster parents: he manipulates his way into being taken into their family unit, takes on their names, then butchers them from the inside.
The email received by Nina featuring Johan's attempt at poetry 'I was born to smother you with roses' may have been an allusion to The Red Rose Mansion
Grimmer is not the only constantly smiling man in this series - Roberto smiles pretty much all the time as well. Which makes sense, given that they're both Kinderheim 511 alumni.