Marvelous AQL unveiled the next Valhalla Knights game's website, which includes the tag-line, "A fallen paradise called Prison." This refers to the setting, Prison Castle, where the characters are sent to uncover a hidden treasure.
The impression you got from above is correct in that the site currently has some character art:
If the above samples pique your interest, be sure to check out the site itself!
The first two games in the fantasy-action series were released on PSP in 2006 and 2008 and both made it to North America shortly after. Valhalla Knights 3 is slated for early next year in Japan, so it's probably only a matter of time...