Tophet is a desert planet that SICON planned to use as a base in the Arachid-SICON war. When Razak's Roughnecks first land on the planet, they discovered that it is already home to a species whom the humans would call "Skinnies" due to their tall thin appearance. SICON ends up at war with the Skinnies, who are allied with the Arachnids. Extremely hot and arid, Tophet has high levels of methane gas in its air. This planet is important to the Arachnids because of a resource named Xylon that enable Transport Bugs to travel across interstellar space.