I definitely have no authority on character accepting, but I am guessing Dark is going to want some stats for sanity costs on abilities. You wouldn't have seen this, but he has asked for us to have four specific moves in your movepool. Most have used them for attacks or spells, though I used one just for a dodging move. So far the different types of moves appear to be....
-Magic
-Ranged
-Melee
Not that it is locked to that, that is just what appears standard.

Again, I can't say what he will accept or not, but taking care of this^ before he looks it over probably will improve chances.