Hi! I'd like to suggest the following for the Dark Knight:

He needs one more combo at lower levels, because sometimes it gets really boring doing the same combo over and over again.

I'm not too fond of the combat stance — I feel like it could be improved. Let me explain: it reminds me of Sephiroth’s stance, but being that crouched down looks odd. He should stand more upright. Some might say it’s because of the sword, but the Dark Knight is supposed to have brutal strength, so staying more upright shouldn't be a problem. It’s true that the stance should give a sense of weight, but the idea is that each sword swing should make the earth shake, lol.