There are a number of races on the world of Nakana, with humans dominating through population. However, humans are ruled by the Katar, a group of extended families that rule backed by power of 5000 rings that give them special powers, longevity by draining the ka from humans. Ka is the life force similar to that of ancient Egypt mythology. Ka is also used by other races to create talismans, which are the backbone of magic, or technology, depending on your viewpoint. Talismans are fueled (after formation with ka) with qenar, a force found in jade. Think of qenar as a fossil fuel, but very limited.
The series follows the revolution against the Katar.
Book One: The Katar Legacy.
Book Two: The Gods of the Katar, while it finishes some aspects left open in Katar Legacy, it takes the reader beyond the revolution, setting the stage for a focus on different characters.
In general, the books are intended to stand alone, despite being a series.