First I used some GS to make the horns , tentacles , etc :
Then from a black priming and white base coat I started to applying very thin layers of inks and very diluted paint, untill I started to reach the desired tone for the skin.
Then I created a cool display base for him to rest there while he's not killing and crushing enemies :)
And here are the final pics:
Hope you like and please feel free to comment !