Erebus

Appearances

 * Persona 3: FES: Final boss

Persona 3: FES
Erebus is the grand manifestation of humanity's grief and negative emotion in Persona 3 universe. He appears as a large, dual faced monstrosity. He is seen in the playable Epilogue of Persona 3: FES, titled the Answer.

After reuniting the separated keys of traveling back to time, Aegis decided to go back to the time where the protagonist performs the miracle of sealing Nyx. As Metis questions about the protagonist' actions of doing so, as Nyx herself is not malevolent. It is later revealed that, in actuality, the protagonist was trying to seal Nyx away from Erebus and humanity.

As Erebus is the manifestation of humanity's grief and negative emotion, by coming in contact with Nyx would awaken her, and thus bringing the Fall. Erebus seeing the protagonist as a hindrance of contacting Nyx, tries to break the seal, who happens to be the protagonist, now turned into a statue and bounded between Nyx and humanity.

However, Erebus's effort has no effect, despite trying to destroy the seal again and again. Noticing SEES's presence, Erebus changed his target to Aegis, as she now shares the same unique ability as the protagonist and hoping to use her as a weapon to break the seal.

Not wanting to give up, SEES engages Erebus, but knowing that even they have defeated Erebus, he will reanimate, as long as humanity wishes for the coming of Nyx. Realizing this, the remaining members of SEES swore to help the protagonist bear the burden by making the most out of their own lives. Aegis would later make a vow, hoping to change the world so someday, the protagonist may be released from his bounds.