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"The lesson will be taught in due time, Aloy. Until then, we wait."
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Plainson Red Blight

Red Blight growing in the Forbidden West

The Red Blight is a mysterious ailment that is part of a collapsing biosphere alongside Supercell storms in Horizon Forbidden West.


The Red Blight takes the form of long red tendrils or stalks, which can grow in dense clusters. It is described by Aloy as having an unpleasant smell and texture.

While little is known about the Red Blight and its exact mechanism, it is known to spread quickly and is toxic to most plants and animals. Aloy compares its germination to "Shedding like dry skin". Humans are no exception, although prolonged exposure is necessary for serious complications. When standing in Red Blight, Aloy will begin to cough as her health slowly drains. Corpses of animals can often be found within these patches which drop nonconsumable Blighted Meat. Machines and mounts are unharmed by the Red Blight, though Aloy will still take damage if she rides through it.

The Blight appears to grow best in regions with poor soil quality, such as over-fertilized or swampy soil. As such, it is frequently found around Plowhorn sites. These Blight regions can be indentified using the map function and thus avoided.

Red Blight also grows as red algae, sickening whoever drinks from infected rivers. Atekka refers to this Blight as "Blood Choke", plaguing the city of Thornmarsh. The algae is described as smelling like "rot". Aloy appears unharmed when swimming through these crimson waters.


The Red Blight emerged as a side effect of DEMETER's rampancy: given its tendency to propagate in overly fertilized soil, its spread is likely tied to the accumulation of errors in flora management.

While it has only recently begun to appear in the Sundom and surrounding territories, it has been a problem in the Forbidden West for some time, having plagued the settlement of Thornmarsh for at least three years[1]. It is also possible, albeit unclear, that it has also plagued the distant Quen, contributing to their famine. The Blight was particularly problematic in the Utaru homeland of Plainsong, posing an existential threat to the agrarian tribe.

Once DEMETER was restored to its original form and merged back with GAIA, the Red Blight began to dissipate: within the Forbidden West, most of the Blight has disappeared (especially after Zo and Aloy repaired the Land-Gods in Plainsong). Blood Choke dissipated when Aloy destroyed the dam above Thornmarsh which previously prevented clean water from flushing out the algae.



  1. In the Thornmarsh datapoint, Fashav mentions that he went to the region to investigate the Red Blight in his second year as a Marshal. As he spent a total of five years in the Forbidden West, this would place his journey three years prior to the events of the second game.