Erebus is the most powerful being in all of Arvine's history. He created the gods, he IS everything. He can change to any form. He can do whatever he wants. He is referenced many times across Arvine, through different religious documents, historical reports, old wives tales etc. One of the three characters of Arvine that can break the fourth wall.
The Summoning Edit
Main Article: The Elderfall Edit
Erebus was summoned at the end of the 10th age, by the combined efforts of the gods and several characters on Arvine, including but not limited to Dave, Revan and Mark. He was summoned by all the gods combining their own powers. (Headed by Melme, the god of time.) Also, the 'mortals' on Arvine added their own abilities that they have learnt to transcend the gods, which enabled them to summon Erebus. Erebus then proceeded to analyse all their minds. He could do this, as he was made of them combined. 'Greater than the sum of its parts', so to say. However, this led to problems. Erebus decided that Arvine was no longer needed. He created Arvine because in turn Arvine must create him, and now that he was created, Arvine just posed a threat and no longer needed to be kept around. This then led to a battle with the gods and all the main characters left alive, which he probably should have won. However, there were two 'wildcards' in the equation. Jonandorf and Desdemona. Jonandorf has abilities that go above the gods, and Desdemona comes from before the gods. These two helped keep the battle even, by repeatedly throwing Erebus out of the fourth wall, allowing the people stuck back on the other side of the wall to fight his minions unhindered. Through their combined efforts, they manage to hold him off, but they know they can never defeat him. So Melme decides to send him back in time, but he has to implode Arvine and send it and the essences of the gods back with him. This results in Arvine being destroyed.