Ghroth, also known as the The Harbinger, is an massive, planet-sized Outer God.
Ghroth appears like a rust-colored moon with a single gigantic red eye that it can closes in order to avoid detection. He is known to drift through the universe while singing its siren song The Music of the Spheres. This song is call to awaken all Great Old Ones and Outer Gods that are slumbering on a planet that is passed by Ghroth. This often leads to said planet's destruction.
- Ghroth was not a creation from H.P. Lovecraft, but is a later addition to the mythos by Ramsey Campbell.
- He bears an resemblance to Hellstar Remina.
- He bears a resemblance to RPC-548, formerly known as SCP-1548.