Rom, the Vacuous Spider is a kin of the Great Ones stationed by Kos to protect the barrier between dreams and reality, hiding the many horrors that the paleblood moon should bring.
Despite her title, Rom resembles a gigantic pillbug or a caterpillar rather than an arachnid. She has a silverfish-like tail and a bulbous body from which vegetation appears to be growing, possibly Coldblood Flowers. Her face resembles a chunk of pumice and is covered in eyes, suggesting its connection to the Great Ones.
It's name - "vacuous" - suggests that Rom is brain-dead, to her thoughts are so far beyond human understanding that Rom cannot communicate her findings to humanity.
Apart from when the Hunter attacks her, Rom is completely docile.
Powers and Abilities
Rom was once a scholar of Byrgenwerth whom at some point went through metamorphosis into Kin courtesy of Kos, according to dialogue given by Micolash. Since becoming a Great One, all methods and rituals used to achieve this have been lost to humanity. Since then, Kos has appoint Rom with the task of protecting humanity from the eldritch, casting the world in illusion as to hide the information from an unsuspecting public.
- Given Rom's connection to Kos, it is possible that Rom (apart from the Hunter him/herself in the third ending) is the only successful attempt at evolving a human into a Great One.