Board Thread:Questions and Answers/@comment-29602226-20160831060724/@comment-29602226-20161024165422

I think monsters already produced DE before the current DL. The current DL just mixed her DE with that of every monster, turning them all into partial Succubi.

Most of them didn't need to get SE from humans, and normal food was enough for them (just as human women get SE from food and from the air they breath), but they could supplement if by eating the flesh and blood of human beings and getting the SE contained within.