Well first of all you did wrong is making the colour Black "Pitch black" the darkest black is transparant in Endless Online.
Notice the sprites in the Gfx files have a pitch black background.
Also you filled the inside of the axe with darker black then the outside, which shouldn't be done.
If you don't mind, well actually to late for that, I made a few adjustments.
Even though It's not very well done it shows you a few things.

Notice the difference in contrast between my colours, this way you actually show it's shaded.
Second, try to give it a sharp looking texture by adding an highlight.
To do this you just have to google something like "sharp" or something.
Other then that, try to give the spike an outline, and sorry if mines looks confusing, I spend 4minutes on it.