Frihtz 21 is a planet orbiting the sun of Frihtz, its native (sentient) population is a large insectoid race known as the Knall. They are trying to defend their home against the technologically superior Oppi. The settlements are clumped together for defence against Knall raids, the inhospitable atmosphere. Most of the animals are insects, large and small. The Bonecrackers are successfully used to defend against Knall and native animals. It is a largely desert planet, with sparse vegetation spread throughout in hardy bushes. The Oppi must live in shaded and tinted colonial hubs to protect against the harmful glare of the sun, and the atmosphere. Because of its location in the crowded Frihtz system, it is prone to eclipses, and the sky, with its plentiful planets and frequent planetary eclipses give it a particularly beautiful sky.
The Knall are an insectoid race with a powerful exoskeleton and endoskeleton, making them fearsome warriors, they are very dangerous foes for the Oppi, but the superior Oppi technology gives them a huge advantage. They live largely in caverns under the sand and rock, this makes it difficult for the Oppi to bombard them orbitally or use radar to detect them. In order to raid the caverns the Oppi must engage in close quarters combat, which they aren’t very good at, a tried and true tactic for the Oppi to use is to release bonecrackers in their caverns.