"In everything that can be called art there is a quality of redemption. It may be pure tragedy, if it is high tragedy, and it may be pity and irony, and it may be the raucous laughter of the strong man. But down these mean streets a man must go who is not himself mean, who is neither tarnished nor afraid. The detective in this kind of story must be such a man. He is the hero; he is everything. He must be a complete man and a common man and yet an unusual man. He must be, to use a rather weathered phrase, a man of honor--by instinct, by inevitability, without thought of it, and certainly without saying it. He must be the best man in his world and a good enough man for any world. I do not care much about his private life; he is neither a eunuch nor a satyr; I think he might seduce a duchess and I am quite sure he would not spoil a virgin; if he is a man of honor in one thing, he is that in all things.
"He is a relatively poor man, or he would not be a detective at all. He is a common man or he could not go among common people. He has a sense of character, or he would not know his job. He will take no man's money dishonestly and no man's insolence without a due and dispassionate revenge. He is a lonely man and his pride is that you will treat him as a proud man or be very sorry you ever saw him. He talks as the man of his age talks--that is, with rude wit, a lively sense of the grotesque, a disgust for sham, and a contempt for
"The story is this man's adventure in search of a hidden truth, and it would be no adventure if it did not happen to a man fit for adventure. He has a range of awareness that startles you, but it belongs to him by right, because it belongs to the world he lives in. If there were enough like him, the world would be a very safe place to live in, without becoming too dull to be worth living in."
- Raymond Chandler, The Simple Art of Murder
This is Raymond Chandler's formula for the character of the detective, and it is one that I apply broadly to most of the characters I create, either for games or for my own writing. It started out subconsciously, without any particular awareness of the Chandler quote, and then I heard it in its entirety and it was as if it codified a lot of what I intended all along.
I don't like characters who are never wrong, and who have never been wrong. I want my characters to make mistakes - in games, not to the point of doing it on purpose, but if sometimes you have to be unkind because your character would be unkind, then you sure as hell ought to walk off a cliff if your character wouldn't see it coming - but that is in a large part because I want them to have a chance to make up for them. Not that redemption is necessarily forgiveness, nor a return to a state of purity in this context, but 'trying harder' is a core concept.
I struggle to play mean characters. I don't like them and I don't like portraying them. Partly, this is because I have to be able to inhabit their skin at least for a time, and I worry enough that I bully people in real life without meaning to, just by being large and loud.
In Chandlerian terms, I apply meanness broadly. The hero - and a character should be the hero of their own tale at least - should not be cruel, although he can be hard; should not be tight-fisted, even if cautious; should not despise the faith of others, even if he has none of his own; should not be selfish, even if he is self-sufficient.
Precise codes come and go, but there is always a place in the world for honour of a sort. The hero should keep his word to those who deserve it of him, and find it hard to give to those who don't. He is honest within reason, but never feels bound to speak the truth to those who are false, nor to those for whom the truth brings more harm than good. He will, to borrow from Chesterton's Father Brown, allow a bad man to receive false praise if none are harmed by it, but never an innocent to be maligned. But he ought not to press his code, nor boast of it; his word is his bond simply because it is. He has not chosen to buck the world in this; rather he sees the world as out of step with the way things ought to be done and while not often surprised by the iniquities of those around him, he is disappointed every time.
It is not a requirement that a movie or a book have a sex scene, nor a romance. Too often these things get tacked on and it always feels like it. For a character in a game this is more important still. It is not a requirement of a character that they have a relationship.
"He must be the best man in his world and a good enough man for any world" is at the core of it. If the character can look at someone else and say 'they are better than me', then he should be striving to be better still.