The greatest and most pervasive human flaw is pride, and I doubt we possess the inner perspective or the humility to accurately describe our own faults, much less self-analyze those self-shadow-reflections which we create for fun.
Oh, I don't agree at all.
Pride is indeed a widespread fault, and one I possess in abundance. Arrogance comes easily to me. This has been obvious since childhood: I don't need a character to tell me that.
Much of my personality is built on reaction against my own arrogance.
The shadow-reflections we play in games, now, those make subtler points. We can conceive of nothing that is not, in some way, of ourselves. I can talk myself out of a great deal, if I let myself-- I once talked myself out of love (for a month. Thankfully, she waited).
Playing characters in which this tendency runs unchecked allows me to explore the nature and borders of this fault. Probably, there are things that I miss, but what I learn about my own tendencies is frequently of use.
Aria's pride in her abilities is very much mine. The casual cruelty, born of arrogance, with which she sometimes employs them? That, too, is mine, though I had never thought of myself as a person with the capacity to be cruel.
Is it a perfect picture? Of course not. Is it useful? Oh, yes.
If humans were self-correcting in thought or action, we wouldn't need the million moral guidelines that have been created for us or by us through the centuries.
For us, through evolutionary programming; our instinctive morality (and tendency to occasionally breach it) is pretty closely comparable to that of the chimpanzee (the only other species I know of that commits lust murders. "If I can't have you, no one can! EEEE EEEE EEEE!" Whack).
By us, through social programming. Our communities work out systems of rules they think work well and teach those to their children.
Mind you, I plainly do not share your faith, and I also believe that "good" atheists are a dime a dozen (though I'm not an atheist, either). Not morally perfect, but morally the equal of the faithful.
And I am extraordinarily skeptical of the exceptionally ridiculous assumption that we have somehow in the last half-century apprehended a moral clarity that has eluded similar humans for many thousands or years. We may be wise apes, but we are foolish men.
Circumstances influence what is right and what is wrong. That's another belief Aria and I share.
The ancients muddled through as best they could in an ancient time-- and in the process saddled us with a number of social devices that may have been necessary once but are certainly a pain in the rear today (see, e.g., the value of female virginity. To this very day, a sexually experienced man is admired; a woman, derided).
We muddle through as best we can, now, and are probably saddling our descendants with some odious rules in the process. As an example, most people these days are what my futurist housemate calls "deathists"-- people who believe that death is an inherent part of life and that there's something immoral about seeking immortality. The first "uploaded" human, if that ever happens, will have some steep hills to climb.
The rules we write for ourselves as we muddle through are based, as they must be, on our own observations and beliefs about what helps or harms us as a society. And so, we analyze, correctly or not, and hope that we do not misunderstand our situation too badly.
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Aria, as a character, is a sort of testing ground for approaches and ideas. Whether she's really "evil" depends on your point of view (as always), but she freely expresses traits that I try to suppress in myself. She's an unapologetic elitist, cheerfully arrogant, casually cruel, and has no qualms at all about being sneaky or underhanded. Her endless front is one of intellectual superiority, although underneath she's something of a coward.
At the same time, she's strongly religious and deeply introspective; she's aware of these faults, and uses this self-awareness to drive her ambition of achieving real wisdom-- which, she'd be the first to admit, she's a long way from reaching.
The thing that pushes her the most towards the "dark" side is the obvious: her conviction that she's no longer human. Even if she's right, in Aria's case this is at least partly an excuse. She conveniently forgets that, even as a human, she was more than a wee bit messed up, and many of the most violent episodes of her life, such as the flash of crimson rage in which she killed her grandfather, have come from emotional places that are far from inhuman.