I stumbled upon some old GFX tutorials I used to read, and then I found some really cool images made by pro GFX artists, so I used their images as outlines for my own work.
This is what I made (with some highlights, cloud brushes, warping, liquifying, vector brushes and splatter brushes)
If it's a bit blurry for you, use this link to view the picture:
http://s18.postimg.org/fezp8sw21/firstfury_2.jpg
This literally took me ages. I started this about 3 days ago.
You can use the picture as a tutorial (it's pretty self-explanatory).
For the parts that can't be explained, I'll write down here:
I sharpened the render.
Added some touches (soft-erased part of his legs, darkened and sharpened the chest and head)
Used some gradient maps.