The smaller partner of the binary planet known as Kennesawu. Its thin atmosphere barely supports life, and doesn't hold in much heat. As such, temperatures tends to fluctuate wildly between day and night (as opposed to season by season, as Kennu does).
Kennu and Sawu are mostly similar in composition, with one major exception: some regions of Sawu having extremely high concentrations of monazite ore. This ore is the primary reason for the evolution of the Symtraya's migration pattern. A few other minor ores exist on the surface of Sawu that are hard to find on Kennu, and these other ores drive the Guigu's space program.