Monster anime series cover art

Series Overview

Monster (モンスター) is a psychological drama anime about the hunt to take down a serial killer. To give a better overview of the series, I’m going to need to spoil the first few episodes. But, don’t worry. The series is 74 episodes long, so it’s not like I’m spoiling a quarter of it.

The protagonist of the series is Dr. Tenma, a renowned brain surgeon. One day, a boy comes into the hospital with a gunshot wound to the head. Dr. Tenma chooses to save this boy’s life over the life of the local official his superior told him to operate on.

As a result, the official dies, and Dr. Tenma’s career at the hospital stalls. Still, Dr. Tenma believes he did the right thing by choosing to save the boy, who came into the hospital first. At least until he learns what the boy truly is — a monster.

Dr. Kenzo Tenma firing a gun from the anime series Monster
Dr. Kenzo Tenma firing a gun

The boy Dr. Tenma saved turns out to be a psychopathic serial killer. While recovering from his surgery, the boy kills other doctors at the hospital and flees. At first, there’s no reason to suspect the boy. And so, Dr. Tenma ends up being the prime suspect as the only one to benefit from the killings.

Everything I’ve said here is from the first 5 or so episodes of the series. The rest of the series takes place years later as Dr. Tenma hunts down the serial killer he once saved.

In his mind, he’s responsible for the killings because he saved the boy’s life. If only he performed the surgery on the politician as instructed. Then, countless lives would have been spared. Whether or not that rationale is good is up for debate. Is someone responsible for the lives they save?

Main Characters

As I’ve already mentioned, Dr. Kenzo Tenma is the protagonist of the series. He’s a Japanese doctor working in Germany as a brain surgeon before his life is turned upside-down. Tenma isn’t actually all that interesting of a character, though. He’s not as morally ambiguous as you might expect based on the setup of the series.

Johan Liebert is the serial killer Tenma saved as a child. As a serial killer, Johan has killed many people. But, his ability to kill actually isn’t what makes him most dangerous. It’s his ability to manipulate others into killing on his behalf.

Anna Liebert is Johan’s twin sister. She was the first one to recognize him as a psychopath and is actually the one who shot him. Like Tenma, she views taking down Johan as her mission in life. At times, she and Tenma work together. And at times they chase Johan individually.

Inspector Heinrich Lunge from the anime series Monster
Inspector Heinrich Lunge

Let’s get into some of my favorite characters now. Inspector Heinrich Lunge is a pretty good character. I didn’t like him much when he was first introduced. But, by the end of the series, I thought he was great. He’s kind of like a much more methodical version of Tenma and Anna, not swayed by emotion.

My absolute favorite character, though, is Eva Heinemann. She’s Tenma’s ex-fiance and she has the best character development in the series. I know a lot of people love Johan as a character. But, I’d argue Eva is way more complex than Johan.

And the last character I want to mention is Wolfgang Grimmer. He’s an independent journalist who’s trying to uncover the truth of his own past. As with all the other characters, Grimmer gets sucked into Tenma and Johan’s game of cat and mouse.

Who Is the Real Monster?

Let’s skip all the way to the end of the series now. Episode 74’s title is “The Real Monster.” So, who exactly is the real monster? Spoiler: It’s still Johan. But, the final episode does bring up an interesting perspective.

Throughout a lot of the series, there’s the implication that Johan is a made psychopath. But, by the end of the series, that doesn’t check out. We know he killed before ever being sent to 511 Kinderheim. And we know it was Anna who witnessed the mass murder at the Red Rose Mansion, not Johan.

And in the final episode, Johan gives us some insight into what actually caused him to snap. When they were children, Johan and Anna’s mother had to choose between them. Which of them would she give up to be part of the government’s experiments?

Johan Liebert pointing at his forehead from the anime series Monster
Johan Liebert pointing at his forehead

The trick here is that Johan and Anna looked the same when they were younger. Their mother dressed Johan up like a girl so she could pretend to only have 1 child. She did this to protect them. But, this came with the alleged consequence that she couldn’t tell them apart.

So, when their mother chose to give up Anna instead of Johan, this messed with Johan’s mind. He wasn’t sure why she made that choice. Did she choose to keep him over his sister? Or did she mistake his sister for him? Either way, in his mind it’s his fault that his sister — the only person he cares about — was torn away from their mother.

Does this mean Johan’s mother is the real monster of the story? I don’t think so. Johan never tries to get revenge on her. He doesn’t blame her — he blames himself. He’s his own monster.


In the end, I gave Monster an 8/10. It could have had a higher score if some of the content in the middle was a bit more relevant. There were some episodes in there that didn’t matter all that much. They weren’t filler but they were close.

I also think a good story could have been told in only 12 episodes. The first 8 episodes of the series set up the story well enough before the scale of the series came into play. We wouldn’t have had a lot of the characters. But, I don’t think it would have been any worse.

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2 Replies to “Monster”

  1. It’s been a few years since I saw this series but I seem to recall that his mother’s choice was a bit more complicated than you described. Because first seemed to pick one of her children at random which was something Johan could have understood.

    The thing that got stuck in his head was that she changed her mind and handed over the other child and he never new why. He never knew if the child his mother gave away was the one she meant to or not. Did she mean to give Anna away and keep Johan or could she not tell them apart?

    If their mother’s choice had been truly random Johan could have lived with that. Or at least that’s what he believes but we’ll never really know. It’s the not knowing and constantly obsessing over the question of which of her children she loved more that got stuck in his head.

    1. There are a few things going on here that are important. For starters, the fact that their mother made a choice at all is important. Neither child wanted to be separated from their mother. So, the fact that she chose to give one of them up, regardless of which it was, could be seen as a betrayal from Johan’s perspective.

      Next, there’s the fact that Anna was chosen. Regardless of whether their mother meant to choose Anna or mistook Anna for Johan, the fact that Anna was chosen is key. Even if she meant to choose Anna, Johan would blame himself for being the favorite child and getting his sister sent away.

      Their mother changing her mind after first choosing Johan only complicates things. It gives him one more thing to question (whether she meant to give him up instead), but it doesn’t change the initial betrayal or the outcome.

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