Sauron

Sauron scourges the Undye, feeding off every corpse that festers under the waves. He is indifferent to anything living as long as there is flesh to feed from. His unending hunger poses a crippling threat, his only hindrance being his massive size that makes chasing possible prey difficult. The opposing Rotlords set aside their rivalry when Sauron comes near their chambers, using their combined power to drive the monster back. Even the dauntless Chernobyll knows he cannot take Sauron alone.
Rotlord, Seeker, and Understorian all share the fear that Sauron will run out of dead prey, and begin pursuing live flesh.