It made Skullius feel sick.
Even Sila was stumped. He hadn't thought he'd awaken to such a revelation.
When he had sacrificed his soul for Skullius' back then, he hadn't at all been sure it would work. He knew souls could feed off each other as fuels, but he hadn't thought about the greater effects beyond just saving Skullius' life. The Hybrid Luman's soul was an oddity amongst souls.
To think Fulgardt took inspiration from that.
'Even if he managed to make Rias a Beyond the Veil Stager, how did he bring him to the very peak of that Stage? It only has five levels, but there must be five horrifying Tasks to get through. Rias couldn't have completed them all,' Skullius thought. But then his eyes brightened. This answer to this, he discovered for himself. 'Ah, right. How could I forget?'
It was simple.