This is part of a bigger project I'm working on. You can follow the progress over at my tumblr: thesilvereye.tumblr.com/
I'm basically making a huge reference sheet with all the (mortal) characters from the Percy Jackson and the Olympians and the Heroes of Olympus series. When I'm done, it will have multiple portraits and full body shots of each character and everything will be shaded. So far I've made 25 portraits, and making these is so much fun, it's my favorite part of my life right now.
Characters are as follows: Percy Jackson, Annabeth Chase, Grover Underwood, Luke Castellan, Thalia Grace, Jason Grace, Piper Mclean, Leo Valdez, Hazel Levesque, Frank Zhang, Reyna, Clarisse La Rue, Nico Di Angelo, Rachel Dare, plus a Stoll brother. All of them belong to the wondrous Rick Riordan.