Good start
Its good that your background colour is low saturation and 50% brightness.
Some advice...
Poses:
The way the guy is standing is a bit stiff as well as boring.
Its mainly his arms are too straight down and his legs need some work.
The dragon pose doesn't seem balanced properly and his tail is just kind of hovering which makes him look like a statue (even a statue would do something more interesting).
Character design:
His face is so generic and the concerned look on his face just doesn't shout "badass warrior" to me.
His skin is too white for a guy who walks around with no shirt all day.
The pants and shoes just look like every day jeans, not very interesting.
So many large blades on his back and their angles just looks weird.
Colours:
There are several reasons not to use so many similar colours but ultimately your not doing anyone any favours.
So reduce your count to 2 or 3 shades per block.
Just flood fill the middle shades with existing colours you'll keep, then increase the contrast of whatever is left over (even just use your software's contrast tool).
Then you will want to look up "hue shift" and apply that to your palette.
Here's a similar kind of sprite I made recently lower res in case it helps.
Sorry its 2x scale its the only copy I can access from here...