I want to start by sharing a funny little video I put together with Window Movie Maker for my Youtube Channel.
I want to give my perspective on the debate of if Kyubey truly qualifies as Evil.
I apologies that I shall do some defaulting to masculine pronouns for a technically gender less life-form, I don't feel comfortable calling any sentient being "it" however reprehensible it is. And the only way to truly interpret Madoka as Feminist is to see Kyubey as a powerful man taking advantage of underage girls.
First of all, if his being presumably emotionless and logical is an excuse or even a valid explanation for his insistence on not revealing all the facts before making his contracts? Would Spock consider it Logical to not tell people what their getting into? I think not.
Is it valid to say he only reveals what he's directly asked because he just genuinely doesn't get that people might want to know? Episode 9 refutes that idea. His answer to Kyoko about if Sayaka can be saved really pushes the line of the claim that he never blatantly lies, because the deception here comes from what he adds that he did not need to say. And when Homura (whom he has decided to become brutally Honest with) asks the same question he answers it incredibly different "of course not".
And then in Episode 11 he eagerly reveals to Homura what he has just deduced, without being asked.
But the final question is. How accurate even is the assumption that he's emotionless? Homura never says he lacks emotions but says "that THING doesn't understand human values". His description of his species is not that they are incapable of Emotions but that it's considered a mental illness. We in our history have had a tragic tendency to label things mental illnesses that are not at all uncommon.
He does show emotion actually, a few times he is surprised, shocked even, at least once shocked with a slight sense of horror in the timeline where he doesn't figure out Homura's deal till the very end. And he also gloats, in the main Timeline we're following, every time he figures out more about Homura. And especially in Episode 11, when he finally finds Humora's Achilles heel.
It's not Emotion he lacks but Empathy, Empathy for Human beings. Because of that he seems like a Sociopath. Now I am often annoyed about how loosely the term Sociopath is used of fictional characters (like when it's used of Joe Pecsi's characters in Goodfellas and Casino, or BBC's Sherlock). It doesn't mean insane, it doesn't mean being a jerk, it doesn't mean a lack of impulse control. And not all Sociopaths become criminals or evil people, plenty become productive members of society.
But if you combine being a Sociopath with an "ends justifies the means" morality and highly "logical" philosophy, you can wind up with someone like Kyubey easily.
So as SFderbis likes to say "Bunny-Cat's a Dick".