I feel like alignment falls more to the character than the power they wield. But it's probably the case that a Dark Knight's darkness is quite likely to have an influencing factor, considering they bear their pain, fear and rage on their sleeves.
I imagine it would be easier for Dark Knights to fall into the 'evil' category, given those factors, but I don't think it's impossible for a Dark Knight to be of a more pleasant disposition. My own character is just that. He's not going about cleaving at people for no reason, and is generally quite polite in casual conversation, but since the darkness awoke within him, he has become a bit more grey morally.
So at the end of the day? I'd say go ahead. Most will think it's a bit stereotypical, or even cliché, but as long as you're happy with the character, then that's what matters.
I imagine it would be easier for Dark Knights to fall into the 'evil' category, given those factors, but I don't think it's impossible for a Dark Knight to be of a more pleasant disposition. My own character is just that. He's not going about cleaving at people for no reason, and is generally quite polite in casual conversation, but since the darkness awoke within him, he has become a bit more grey morally.
So at the end of the day? I'd say go ahead. Most will think it's a bit stereotypical, or even cliché, but as long as you're happy with the character, then that's what matters.
"My anger, pain and sadness—shall be your loss."
(Tumblr, if you give a damn -Â http://thelifeandtimesofrufus.tumblr.com/ )