Blightlands

"The Flood can survive and grow in almost any environment, but it thrives in a surprisingly narrow band of habitability. The interior of Flood hives provide a controlled environment for accelerated growth, but in time an entire planet's biosphere can be altered to approximate these ideal conditions."

— Phoenix Logs

Blightlands are Flood infested areas which serve as the first step of the process to convert their environment to suite the Flood's biological needs. Flood Hives develop specialised forms which harvests vitality from the soil, absorb solar energy and consume native life. These zones are eventually consumed to provide raw material to Flood Spore Mountains and Flood "organs" that finish a planet's ruination.