Everything started from a conversation on the River Styx. At the time, Ayer was rowing a boat while having a seemingly casual conversation with Roland. What they were speaking about, however, was a massive scheme that involved the entire world (Chapter 66).
"By the way, Roland, didn't you mention Hell and the netherworld? And how demons resided within these places in your world? Do you know that there's also a Hell in our world? It's just that devils live there, instead. I talked about your plan with Little Tias. If you're truly capable of creating your vision of Hell and the netherworld, he's willing to give all of Hell over to you and even make the devils learn how to become Hell's prison guards."
