Structi are a kingdom of life inhabiting the planet Impendia, characterized by their growth patterns and symbiosis with other lifeforms. Structids form entire colonies and cities which are functional to its inhabitants, and are, along with the haze-archaeids, a source of inspiration for stories and religious beliefs.

Although structi carry great significance to native populations living on the planet's strateaus, these organisms have been in danger of extinction for thousands of years, a reason why Xolhengian legend holds that the god Um will return and clear away the hydrocarbon smog, revealing vast cities of the organisms.