Apparently a companion piece to Percy Jackson’s Greek Gods will be arriving next summer. According to Rick Riordan,
During the Blood of Olympus tour, we announced Percy Jackson’s Greek Heroes, which will be published on Percy’s birthday, Aug. 18, 2015. This is very much like Greek Gods, except about (you guessed it) the Greek heroes like Hercules, Theseus, Atalanta, Perseus, Orpheus, and all the rest. Filled with Percy’s snark and sass. Illustrated with full-color art by John Rocco. So heavy you won’t be able to lift it. Yes, it will be awesome!
So, there you go.