Celestial essence
"So from what we know until now…"
Elio was sitting inside of his cave this time, and it had been around four months since he came to this forest/mountain top.
"This mountain is the center of the blank area that no one knows much about.
The forest below this mountain is saturated with monsters of high level, monsters so dangerous that they could kill even the strongest of the individuals.
There are hundreds of them down there and only the strongest of them can climb the mountain and reach this 'paradise' which directly connects them with the high heavens."
[{ Ummm… master? Why are we calling the river the high heavens? }]
"It simply sounds good, Sera. Don't mind that."
Sera didn't understand why she asked that question when she knew there was no great reason behind him calling it like that but she ignored it for now.