Quoted By:
In the medieval fantasy world of Álfheimr, succubus princess Astarotte Ygvar, the first princess of the kingdom of Ygvarland (ユグヴァルランド Yuguvarurando?), has just reached the age of 10. 10 years old is a special age for a young succubus, as it is when they are traditionally expected to form a male harem.
In order to maintain their body and preserve their beautiful appearance, Succubi who have undergone puberty must consume male essence, much like how a vampire must consume blood. Initially a mere kiss will suffice, however as Succubi mature into young adults they eventually need to consume a liquid called "sáðfryma," better known as semen, to sustain themselves. The harems they form ensure a steady and safe supply of the liquid.
The princess, however, bears a great dislike against men, and only agrees to create a harem if a human male is to join, as humans are said to be extinct. However her followers are somehow able to find a human male named Naoya Tohara who, along with his daughter Asuha, is brought to the demon world to be part of Astarotte's harem.