'Veteris 42820 is an ancient planet_ about twice Earth's age. It has been lucky to avoid major asteroid impacts, and the number of mass extinctions throughout its history have been minimal, and far less severe than in our own. This fact, combined with Veteris’ highly diverse geology and stable climate, means that many of the planet’s original biological genera are still in existence - albeit in highly evolved forms.'

— Exobiotica, Veteris

On Veteris, growth seldom occurs in isolation. Cooperation is not an exception to the planet’s ecology but one of its governing tendencies: relationships that may begin in competition, predation, or dependency often shift over time toward increasingly reciprocal forms of exchange. Energy itself is acquired through similarly hybrid means. Many organisms supplement feeding with photosynthesis, with the degree of autotrophy diminishing as mobility increases; others alter this balance throughout their development or in response to environmental conditions. The result is an ecology in which survival depends less on discrete acts of consumption than on entanglement, adaptation, and prolonged interdependence.

Ilythis represents, one extreme articulation of this principle; a juvenile, drifting organism whose body has become substrate, vessel and habitat to an entire flora. Nourished by the planet’s attenuated, low-spectrum light and by the creature’s own circulatory processes, this vegetation produces a buoyant gas that sustains the body in suspension throughout its prolonged adolescence. The association is not, however, strictly mutualistic. Throughout ontogeny, Ilythis progressively modulates the genetic expression of its associated flora, favouring phenotypes tolerant of the reduced irradiance and elevated hydrostatic pressures characteristic of its mature habitat. This induced adaptation facilitates the eventual transition of both organisms from a mobile juvenile phase to a sessile, permanently rooted, deep sea, adult state.