User blog comment:Menara/The Mark of Athena Character Art Revealed!/@comment-4485028-20120909133300

Looks like Arachne has an official description http://disney.go.com/official-sites/heroes-of-olympus/hercules

It seems that besides Coach Hedge, the background for all the MoA character art reveals have had their backgrounds changed to the same purple-ish thunderstorm that's on the cover.