Riddick is a character from the "Pitch Black" and "Chronicles of Riddick" movies (and one badass video game). Riddick is played by Vin Diesel. Basicallt this Turian just looks like a Turian version of the character from the movies.
This is just so cool and fantastic I have trouble processing it! Being such a huge fan of your work it was one of the most awesome gifts I've ever gotten, so thank you so much in turn ! It's just so so cool, you draw one wicked turian!