The Naski's planet had rapidly changed to be inhospitable in the past 30-50 years due to the sudden growth of a parasitic plant-like life form called xiya. The Naski are telepathic and Xiya was notable for interfering with their telepathic processes, sometimes causing hallucinatory telepathic episodes and leading to paranoia and psychosis. These effects were highly detrimental to Naski society, which collapsed as the xiya spread.

Setsun was one of the last Naski living in the city of Ossoth, deep within the jungle. She is notable because she attempted to chronicle the fall of her civilization before she was murdered by her own brothers who had succumbed to the psychosis-inducing xiya.

Interestingly, a small subset of the Naski population was not telepathic. They often were forced out to live in smaller outcast communities and many still exist, as they were not as affected by the spread of the xiya.