From Introduction:
Papilian (pronounced pah-pil-yun) is the second planet in the Gai system. The world is slightly smaller than Gaianar, has lighter gravity, and is hotter. Most of the forests are jungles and most of the plains are savanna. Papilian does not have the problem of Stillpoints that Gaianar has, but it does have its own unique ecological crisis known as "The Ruining."
Whereas Gaianar has strong connections to both the Dark Matter Realm and the Imaginary Realm (which explains why Mathematicians are both common and powerful, and why Gaianar's technological era happened so quickly and early on), Papilian seems to have strong links to the Abyss, and the Plane of Light (which explains why the religions have polarized into only two forms - Good and Evil, and why the Avatars of these concepts actually take up residence on the planet).