Scott Snyder confirmed that there is a link in a Talksplode interview. He and Jeff Lemire are good friends and they share scripts. Snyder said it's less of a crossover at this point (though they have a story planned) and more of a shared universe. The "villain" is another elemental force, which is neither good nor bad. He said it's a case where any of the forces, be it the red, the green, or the "villain" work best when they are in balance. When any of them are dominate, it's a bad thing.