I love playing villains.
Although I personally don't believe in "evil," as a concept (I'm with Kurt Vonnegut on the subject of human nature), I do believe in destructive thought patterns and the vast power of the human brain to do itself (and those around it) a mischief. People can rationalize in amazingly sophisticated ways, and our moral barriers are subject to change with sufficient application of logic.
That being the case, I tend to play highly intellectual forms of "evil," the sort that get around their moral qualms by reasoning them away rather than by ignoring the issue. It's an approach I'd suggest to anyone who is interested in investigating how intelligent, introspective people we would normally view as "corrupt" think.
Examples of this character type within Eve:
* A conservative Amarrian cleric, deeply knowledgeable, who believes the Minmatar as a people have forfeited their place in God's kingdom through rebellion, and must therefore be destroyed.
* A bookish Sani Sabik nihilist (of Nietzsche's school), who genuinely believes that "life itself is the will to power; nothing else matters," and seeks to expand his own power by any means available.
* An Equilibrium of Mankind member who looks on humanity as a plague, not just to the universe, but to itself, as well, and, seeing suffering as endemic to humanity, seeks to end it-- by ending the human race.
Suggestions for those who want to try this:
* Figure out your own more absolute barriers and work within them.
Constantly fighting the part of your brain that screams "NO!" every time you make a choice as your character is tiring and not much fun. I, personally, find it easier to callously blow up ten thousand fictitious people than I find it to be an inconsiderate jerk to just one, so my characters tend to be very polite monsters.
* Work out, in detail, where your character is coming from.
The fun part of playing an intellectual villain is getting down the twisted or subverted worldview. Religious fundamentalism is a highly-workable angle, as is jaded nihilism. Moral relativism can also lead to some fun places if you can work out an argument for why your own "relative" place calls for different morality from everybody else's.
* Don't try for perfection.
Getting in philosophical arguments is a "perk" of this approach. During the course of these, you will make mistakes. Unless your character is a megalomaniac, it will work to your advantage to admit to these, adjust your argument accordingly, and move on. Your character's worldview should be flexible enough to let you do this. Inflexible zealotry is for callous badasses and raving cultists, not thoughtful, sophisticated monsters.
*Corrupt, twist, distort, and corrupt some more.
A hallmark of this kind of character is that she thinks-- is downright convinced-- that she's right. This isn't the sort of "being convinced" that leads to unquestioningly following orders: the orders will be, all within the space of a breath, mentally questioned, found to be valid (or not), and followed (or not). The kind of character who does that will likely try to bring others around to her own point of view. After all, if they only understood, they'd see the truth in her words and join her.
Watch for opportunities. Plant seeds of doubt (or at least curiosity) in the minds of "younger" pilots and try to intercede when a more experienced one is experiencing a crisis. There's nothing like "counseling" a soul in torment to bring another believer to your side.
* Don't lie unless it's important.
Again, your character acts as she does because she has thought it all over and thinks she's come to the right conclusion. Such a character might not have many qualms about telling lies, but telling lies makes people less likely to trust her in the future. If she's going to spread that truth, it will be important for her to be trusted.
* Allow for growth, even redemption.
Playing a character functionally damned by her own logic is a blast, and watching people trying to navigate the maze to lead you back out is one of this angle's greater pleasures. However, if there is no way through at all, this will eventually get boring, with the character stuck in stasis. Change and redemption should be possible, but the "savior" should have to be an ace at getting between other people's ears to pull it off.
Intellectualizing a moral issue away is necessarily a process of rationalization, which serves as a shield against the parts of the brain that keep right on screaming "NO!" ... Unless the character is a psychopath, in which case, there's no "screaming bit" to shield. If there's anything there that can be "saved," there should be some key, some way to get through to the character.
This should by no means be easy (such characters should roll their eyes at almost any form of emotional appeal), and redemption need not be permanent.
Backsliding is fun, too.