Succubus

Encyclopedia Entry:

A greater demon possessing extremely powerful abilities that lives in the demon realm, etc.  They are also called “inma.”  They appear in various places in search of human men even outside of the demon realm.  Some of them assume a human form and take up residence in human settlements.  The majority of the monsters that have changed into the form of a woman and begun feeding on human spirit energy have done so due to the influence of the demon lord, however, the succubi are a race that have always had the form a woman and fed on spirit energy, even ages ago.