A gentle and observant young man who specializes in the healing arts. He is always accompanied by a small white plover named Selene. While he is soft, he is not weak, and he will stand up for his beliefs and protect those he can.

Erebus is the second (and last) scion of House Silvermoon, a family of doctors and scholars which once served the Queen and her court. The House was eliminated during the Hundred Years' War as punishment for high treason, supposedly committed by the House leader Nyx Silvermoon. Erebus was not spared from the wrath of the Queen due to his status as Nyx's younger brother, even if he was not directly involved. However, he managed to escape with his life and was diminished into a Treat instead. With his home destroyed and finding nowhere else to go, Erebus was then exiled from Treatropolis and wandered the Realm of Dreams for many years as a Treat. His ignorant vagrant existence finally came to an end when he met Serras and the Pirate used his connections to bring Erebus to the Treatropolis Sun once more.

Erebus often travels throughout the Dream (and sometimes Nightmare) Realm, offering his aid to those he can help. He was taken in by Verde as a pupil, and built a small residence within the green kingdom. He still holds onto the belief that Nyx may have survived and is hiding out somewhere in the Nightmare Realm. He is always on the lookout for any news about his missing brother.

Rather unfortunately, he is allergic to momes.