* CompleteMonster: [[GodhoodSeeker Keith White]] is the head of a research group that uses humans--[[WouldHurtAChild usually children]]--as test subjects for [[ForScience painful, unethical and often deadly experiments.]] When Alice asks if she and the children could just see the outside world for a second, he hits her, then he has all of the children shot, which leads to Alice being shot and merged with an alien lifeform, something which he shows absolutely no sorrow or regret over. When a colleague denounces the experiments as unethical, Keith laughs at him. Then, he creates multiple child clones of himself and implants them with nanotechnology, causing most to turn into monsters and die painfully. Even later, he shows up, taking over Keith Black's body and is thrilled at the thought of Alice launching a nuclear missile and driving the Jabberwock to blow up America with anti-matter. When Keith Violet tries to talk him out of it, he tosses her off of a building. He also kidnaps Katsumi, possessed by Alice, to get her to be taken over by the ARMS Bandersnatch and freeze the entire world. Finally, he kills [[spoiler:[[OffingTheOffspring Keith Blue, his own son]]]], with absolutely no remorse.
* JerkassWoobie: ''All'' of the Keith series can be seen as one. [[spoiler: They were all clones of Keith White, a CompleteMonster MadScientist who sees them as nothing more than tools. Keith Red died in despair after trying to kill Jabberwock, lamenting the Keith series' the-strongest-is-king mentality. Keith Green died helping Ryo reunite with Katsumi, who he [[LoveRedeems was in love with]]. Keith Black/Cyril seemed like a true villain until you learn of his childhood, where he UsedToBeASweetKid until Edwow was sent away to form the [[LaResistance Bluemen]] and became Keith Blue. It's even revealed later that White had a hand in his actions as the adult Black. Even Silver, the most aggressive by design and the second strongest after Black, showed a moment of compassion for Green, and pretty much died the way Red did. and Those not mentioned here were all killed by Cyril/Black or were good guys.]]
* {{Narm}}: Ryo and Hayato meeting for the first time. Ryo offers his hand to shake, and it suddenly cuts away as a loud slap dramatically echoes through the homeroom. We cut back to Ryo and Hayato as the entire class is staring at them, revealing that the noise came from Hayato smacking Ryo's hand aside. The real narmy part comes from Hayato standing stationary, angrily avoiding looking at Ryo, and keeping his hand in the post-smacking position for several seconds. It's more dramatic than it should be.
* PacifiedAdaptation: While the anime does have some violence, many of the more gruesome moments from the manga have been toned down or even excised entirely. Some of the more notable examples include:
** In the anime, Hayato’s father is killed by Keith Red swinging his massive Arms blade at him, knocking him back and seemingly cutting him down (though neither blood nor wound is explicitly shown). In the manga, Keith Red just straight up decapitates Hayato’s father.
** The Chapel twins Jeff and Al’s backstory is trimmed down significantly in the anime, only hinting at them being ostracized by their classmates due to their intellects. The manga goes into more detail about the extent to which they were bullied, culminating with them murdering their classmates in cold blood and then shooting their parents when they tried to kill the twins for committing such atrocities.
** At Abumisawa, the Arms boys bear witness to the failed experiments that were performed on people before them. The anime only shows these people in silhouette, leaving detail to the viewer’s imagination. While it can be argued that NothingIsScarier, the manga makes great use of Ryoji Minagawa’s artwork to show just how horrific and painful the failed Arms experiments are on the poor souls afflicted with them.
** During the snark hunt, a little girl with a teddy bear is taken hostage by the Red Caps and witnesses her father get shot for begging to take her place. The anime later shows the father reappear alive and well (save a broken arm) for a joyful reunion with his daughter. No such luck in the anime, where the father is shot in the head and doesn’t come back.

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