As a result of the high level of depleted hyperdrive coolant, toxic radioactive rivers of hyperdrive plasma flooded the region, which coupled with the dark and cold climate of Erebus and the corrosive acidic rainfall, made the Nightyards an effective, if eventual, death sentence to most who worked there. Prior to being discovered by the then-Harbinger, Mercius Nothian, Krovo Scrios was a member of the Thrall Caste that was bound to the Nightyards.