Remember when this show was first airing? No one knew where the hell the story was going. It was conversation this, pretty pictures that, Senjougahara Fascination this, borderline pedophilia that. It looked more like a slideshow of all the sick fantasies Nisio Isin wanted to partake in when he decided to write this story, and given the stunning detail and cinematography of each prepubescent piece of ass that was thrown our way I wondered if there was going to be a story at all. Turns out there was two stories to be told in this anime, one focusing on Karen and the other on Tsukihi, but there’s a more interesting character to discuss and that’s Kaiki Deishu.
Coming from a long line of office space backstabbers and dodgy hairdos evidently did not stop Kaiki from being unconditionally and irrevocably evil in Nisemonogatari. He cons little kids into hurting each other on the middle school playground and profits from it, quite handsomely I might add. He looks at you and scoffs at each and every one of your actions, knowing full well that he can outdo you at any point in time because it’s in his full power to do so. He is the pinnacle of pragmatic self-gain, and a caricature of the fears and loathings that ordinary citizens like to plaster onto capitalist pig. If the right amount of money and power is involved, you bet that Kaiki is involved, and everyone would be in the right to fear that. This is because he is Neutral Evil: the worst and most evasive kind of evil.
Ethical neutrals view […] lawfuls […] as extreme. They see lawfuls as overly strict and rigid […]. Ethical neutrals feel that they take a practical approach to matters involving rules and regulations.
Although labeled as “evil”, characters with this alignment tend to view themselves as determined, assertive, and full of conviction. To these characters, “good” is simply self-righteousness and the promotion of the weak over the strong.
~How Neutral Evil views [Lawful Good], Source: easydamus
The best way I can explain this comes from the interaction between Karen and Kaiki in episode 5.
Karen, the wannabe protagonist of her story and an example of Lawful Good, cannot stand Kaiki because he evades all the profiles that she’s familiar with. To be a hero, she needs someone she can reliably call evil in order to complete her. She needs an image of someone that is easy for her to justify smashing, a flaw she can easily prove wrong. Opposites who are foils of each other tend to feed off each others’ energies and empowers them further into substantiating each of their own ideals. It would be a perfect yin-yang relationship that would have defined Karen as a bonafide hero, but only if Kaiki were to behave as she expected a villain to behave. He has to have some sort of stake in specifically terrorizing little kids, some sort of deep-seated reason or ideal for her to bring down along with his regime. Yet, Kaiki has neither an ideal nor a regime for which Karen requires to take down. What gets to her most about this man’s character is how much he doesn’t care, period. Sometimes the worse kind of evil is the one you don’t understand.
He has no higher reason for being evil other than for his own personal gain. He cons kids only because it’s easier to pull off. There is no handle, no apparent weaknesses, to which Karen can elicit a reaction out of Kaiki with. He’s not evil because it’s fun but because it’s logical and reasonably easy to pull off without repercussion. The money, Kaiki’s main reason for conning people, is something that is painfully relatable to human society in general, something that Karen cannot argue against. So, he responds to Karen’s fiery barrage of insults with little to no emotion, which means that all the energy she just directed at Kaiki wasn’t coming back to her. Soon her upbeat demeanor shrinks into anxiety, fear strikes her face, and it only take a tap to the forehead from Kaiki to bring her world crumbling down and separate her from the spare change she still had on her. Really, she had it coming from a long ways away for trying to confront him one-on-one.
Do you know what’s even better? He practically gets off scot-free because he’s a sleazy little bastard. The moment Ararararagi and crew are onto him he just leaves, and that’s the end of the evil deeds of Kaiki Deishu in this city. There is no satisfaction to his defeat because it was initiated by him, none of his victims got their justice, and he does not stop being a con artist. Since he has no immediate attachment to his crimes, it’s increasingly easy for him to disengage and just find another way to get more money. He may be breaking the law through his misdeeds, but he takes advantage of the times where it’s probably best to lie low for a while, all without having to completely change character or some bullshit like that. You could easily mistake him for some odd money-grubbing fellow with a useful tip or two at your local Mister Donut, but he wouldn’t be any less evil because of it.