Mystery, Hidden Sword

"Just as I thought..."

When he saw the portal abruptly appear and swallow Benia, Roy knew his suspicions had been confirmed.

The souls of demons from the Abyss World all bore the Ouroboros Mark, which was essentially a unique label marking their fundamental difference from demons born in other worlds. This difference also carried the meaning of "orthodoxy," which was why the Abyss World was called the homeland of demons.

The first demons must have come from the Abyss...

And because of the Ouroboros Mark, demons of the Abyss World had a special Abyssal ritual whenever they advanced. Starting from the moment they became Demon Lords, they would be drawn into the opened Heaven's Gate and enter the domain of Holy Light. This ritual served, first, to proclaim their valor and glory, and second, to make it easier for demons to seize the Ouroboros Marks belonging to angels, ultimately forming the Mobius Ring needed to synthesize Divinity. The same applied to Heaven; angels also had to enter the Abyss World and hunt demons in order to advance.

No one knew where this ritual had come from, but it had been engraved into the genes of demons and angels, causing both sides to slaughter one another without end for all eternity. This was the true origin of the Eternal War.

Of course, the prerequisite for this ritual was a normal advancement path for Abyss Demons... Since there was a normal path, there were naturally abnormal ones as well. There had likely been many such cases over billions of years. As long as the chance of an accident existed, it was bound to occur among enough samples. And clearly, Roy's advancement had been an abnormal case.

In the Bayonetta World, he had killed Jubileus, an Archangel at the Demon King rank, with