Fresh blood

Blood Moon Gu is easy to feed, much easier than Golden Moon, Frost Moon and Illusionary Moon: its food is no longer moon orchid flower petals but fresh blood. The blood needed is a lot, but it is not limited to one type of creature: that amount might be a problem in the Western Desert, while the Southern Border’s forested and mountainous areas hold all sorts of wild beasts, so killing them puts the Gu’s food everywhere. ^{ch. 157}

Fresh crocodile blood, gathered from six legged crocodiles killed on a river beach, can be used to feed Blood Skull Gu and Blood Moon Gu. ^{ch. 205}