Comprann (CP)

Comprann is a terrestrial planet notable for its extensive subterranean biosphere and unique civilisation. While its surface remains largely uninhabitable, the planet's vast network of underground caverns supports a complex ecosystem and hosts the native Compranni species. It is a member world of the World Unity.

Physical characteristics

The planet's surface is predominantly composed of weathered basalt plains and impact craters, with an average surface temperature of 318K. The atmosphere is thin but breathable, consisting primarily of nitrogen and oxygen. Below the surface, an extensive network of interconnected caverns spans approximately 60% of the planet's habitable zone, ranging from depths of 100 metres to 3 kilometres.

Indigenous life

The dominant species, commonly referred to as Compranni, are humanoids characterised by their tall stature (averaging 2.1 metres), melanin-rich skin, and complete absence of optical organs. Instead, they possess highly developed echolocation abilities and can detect magnetic fields, adaptations that enable efficient navigation in their lightless environment.

The cave systems host diverse flora specially adapted to low-light conditions, including:

• Phosphorescent fungi networks
• Deep-root vegetation systems
• Mineral-dependent plant species

Society and culture

Compranni civilisation is structured around vast underground metropolitan complexes connected by tunnels. Their architecture emphasises acoustic and magnetic properties rather than visual aesthetics, reflecting their sensory orientation. Cities are typically organised in acoustic zones that facilitate navigation and communication through sound reflection patterns.

The planet's artistic traditions focus heavily on sonic and tactile experiences, with particularly sophisticated developments in musical composition and textile arts. The Compranni have no concept of visual art or colour, instead developing rich traditions in acoustic sculpture and resonant architecture.