"One theory is that it's Earth Demon Seven, another says Earth Demon Eight, and yet another possibility is that both Earth Demons might be there! But if it's the latter, releasing them when the time comes will be extremely tricky!"
"What do you mean?"
"Over the long passage of time, if two Earth Demons are placed together... demons are naturally combative. If one devours the other, it is highly likely to ascend and become a Heaven Demon."
Chapter 800