Beauty is in the eye of the Eyemander
Don't mess with the casters of the beach.
(NOTE: User was awarded 25 shmuckers for this post. -Rob)
Well, it's obviously a joke on the phrase "beauty is in the eye of the beholder", only beauty is not a concept, but a beautiful girl, and a beholder is not someone who looks, but rather a d&d monster Beholder (basically a flying eye with a giant mouth and extra eyestalks growing from top). And all this is given an Erfworld spin where beautiful girl is an Archon, and Beholder is Eyemancer's aberration.
I can't add anything to Elecampane's thorough description, except that Dungeons & Dragons is now owned by a company called Wizards of the Coast (which is owned in turn by Hasbro), and the text about "the casters of the beach" must be a reference to Wizards of the Coast. I don't get the "Fight On!" either.
I think the beholder monster is a running gag, often used to ridicule Wizards of the Coast's excessive litigation and anti-proliferation policy, which is inappropriate because a lot of their work is inspired by cultural myths. They try to manage their intellectual property like a tight business, but it has lost them many fans as a result.
This art looks creepy, but I support the idea behind it.
Yeah, the "Fight On!" and salute are clearly a take on the World War II posters; my first thought was that this was supposed to be a Charlie propaganda poster. And errantknight's airplane art idea might explain why the archon's artwork is different from the rest of it (no shadows, more pale outlines, etc.).
As for the tentacles, it took me a bit to connect "eyemancer" and the fact that the middle one reminded me of Issac, and then I noticed the tags: Second from the left is Pamelor Ambien, fourth is Tisha. The leftmost and rightmost I have no idea -- though you'd think that gas/NIOSH mask would be a dead giveaway -- but I assume they are other background members of the Great Minds.