From the back cover:
Threats from the South
The Scarlet Brotherhood has always been a mystery. Cloaked in shadow, manipulating events across the Flanaess, exploring unknown southern jungles, the Brotherhood influences the world in ways both obvious and subtle. Now learn their early history, hierarchy of power, gods, and agenda.
But the Brotherhood is not alone in the south. Explore the peoples, nations, gods and wonders of the continent known as Hepmonaland and the jungle peninsula of Amedio.
This book includes new character classes for Scarlet Brotherhood monks and assassins, as well as speciality priests for the entire Suel pantheon.