Board Thread:Questions and Answers/@comment-29602226-20160831060724/@comment-24851346-20160913191431

Well we know that Monsters can live off typical diets like from meat and vegetables. Even in Demon Realms. They prefer to get their energy from men when possible, but they'll eat regular food for taste and nutrition. So presumably they subsist off of the Spirit Energy there if it's necessary for their diet.