User blog comment:Call me Nappa/ATTENTION ALL ARTISTS!!!!/@comment-4957813-20140625201229

Gray has listed some guidelines in the FAQ section of his post. The two biggest things you need to know are:
 * 1) They are taking multiple submissions
 * 2) They are not yet ready to accept OCs and original weapons. They will make an announcement for when they will accept those. So for now keep the artwork canon.