A mad scientist is already a terrifying concept, giving rise to all kinds of terrors that include everything from resurrection via electrocution, biological weapons, and all kinds of body horror. Anime has its share of dangerous scientists, and some of them are good, but let's face it, the most interesting ones are evil, totally amoral, and lacking any kind of morals or ethics.All the following characters took center stage as primary antagonists at one point in the anime in which they appeared. They invoke varying degrees of sympathy in viewers, with some a simple caricature of the dangerous scientist trope and others more complex figures with their own backstories and arcs.
7 Souichi Tomoe – Sailor Moon S
Probably one of the more sympathetic of the motley gang of dangerous scientists that populate the anime genre, Souichi Tomoe appears at first to be the dedicated professor who is devoted to his daughter and the memory of her late mother Keiko. This mild-mannered lab rat has another, much more sinister side, which takes up most of the plot of Sailor Moon S.
Tomoe isn't exactly himself. The demon Germatoid possesses his body for most of the series, which is the meaning of the symbol often depicted in the right lens of Tomoe's glasses, influencing him to lead the Death Busters and work with Mistress 9. When Germatoid left him to fight the Sailor Senshi at the end of the season, he was freed from its evil influence.
6 Medusa Gorgon – Soul Eater
Dr. Medusa was initially an ally of the good guys in Soul Eater, a kindly doctor who also worked as a nurse at the Death Weapon Meister Academy. It was eventually revealed that all of her good deeds were ultimately part of a sinister master plan to make her own son into an ideal killer.
Medusa's treatment of her young son Cronas is probably one of the most despicable things about her, even though the show occasionally hints that she feels some guilt for it. Her experiments didn't just include those in a more scientific vein, like replacing his blood with the Black Blood, but locking him away in isolation for days on end when he refused to kill small, helpless animals.
5 Gendo Ikari – Neon Genesis Evangelion
Gendo has a few interesting titles that reveal his accomplishments, with Worst Father and Creepiest Boss along with one of anime's most dangerous scientists. He's not the only candidate for the title in this series, either, with Ritsuko Akagi and her mother Naoko Akagi also making a strong case.
The Human Instrumentality Project, a global experiment that used the whole population of earth as its guinea pigs, was Gendo's idea and his ultimate design. His obsession with this plan for humanity led to countless deaths and an impressive amount of destruction. The plot tries to invoke some sympathy for him based on genuine feelings he had for his wife, but it's hard to see him as anything else than an oblivious villain.
4 Shou Tucker – Fullmetal Alchemist
Amiable and nerdy at first, Shou Tucker isn't a very good scientist, or at least that's what he seems to believe. When Edward and Alric first meet him, he's simply another struggling Alchemist in a competitive profession, trying to make a living and take care of his daughter at the same time.
It never feels right that Tucker's wife is on permanent vacation, and the longer the brothers stay the more sinister their environment seems to become. Things finally go off the rails when they discover that Tucker is trying to transmute a talking animal by combining his daughter with the family dog. Suffice to say, what follows is one of anime's most visceral and gory scenes, and not only because of the emotional impact.
3 Caesar Clown – One Piece
One of those non-funny kinds, Caesar Clown is more scientist than a clown and is featured as the main antagonist of the Punk Hazard Arc. This is the first time the Straw Hat Gang has visited the New World, and this dangerous villain was an interesting way of welcoming them.
Ceasar's ghost-like form is related to his Devil Fruit ability, so when these powers are disabled he takes on a more recognizable humanoid form. His sinister plans include blowing up innocent people and drugging children, so they follow his orders and can't escape.
2 The Doctor – Hellsing Ultimate
This character is never given a name past this simple title, and it seems that as long as the Major and the Millennium forces have him around, they don't need any others. The Doctor is a satire of all the dangerous scientists in literary history, including the multi-lens glasses and perpetually bloodstained lab coat.
The Doctor is the character responsible for discovering a way to create vampires artificially, which results in an endless supply of undead soldiers for the Major's forces. It's also theorized that he developed and built the Major's cyborg or android body, so he would no longer age.
1 Mayuri Kurotsuchi – Bleach
Everything and everyone is but a subject to be studied, according to the brilliant but cruel Mayuri Kurotsuchi. He's ruthless when it comes to the subjects of his experiments and crushing his enemies, often combining the two into a cold and calculating destructive force.
There's a unique quirk that this scientist has in the sense that he pursues knowledge but despises the concept of perfection. The attainment of perfection would mean no further experimentation, and nothing means more to this dangerous scientist. Mayuri turned his own minions into living bombs once without their knowledge just to reach two Shinigami agents and use them as test subjects.