Ok, I've tried some variations on the main character:

1 - old version
2 - more contrast, slightly straighter pose, different hair (trying to make it look like flames to communicate his determination

)
3 - detailed clothes, more medieval... ish
4 - even more contrast
5 - black lines
I think I prefer the third one, even if it looses some of the simplicity of the second. What do you think?
I've also tried animating it. Here's a walk:

And here I tried to rotate the head/body a little. I don't like how it came out...

I'm also thinking of adding some frames to make it smoother...
Here are some facial expressions:

And here's the walk in game:

Thoughts?

Thanks!!!