In this world where magics, dragons and wars are ubiquitous, a small kindom lies in the outskirts of the continent (I forgot the name). The name of the kingdom is Trechwartz and its peace was daily threatened by the invading Cartagia Empire. However, the barrier encircling the kingdom (called Great Barrier) keeps the invaders away, thus temporarily sheltering its citizen from enemy barrage. However, the current queen is ailed by a strange rare disease, and her life won't hold for long. If the queen dies, the Great Barrier protecting the kingdom will collapse, exposing them open for invasion. One of the princesses must succeed the throne, and fast!
In this world, only girls can use magic, thus automatically making them superior to men. In every kingdom, they have prepared a concubine of selectively chosen males for the princesses to select from, so that they can mate and produce an offspring with superior magical power. However, due to the previous attack by the Cartagia empire, the repository for male candidates was sabotaged, abducting all of them. Without a male to mate with, Kyoutarou Kamiku was summoned by the five princess as a last resort. To save Trechwartz Kingdom, Kyoutarou must impregnate one of the princess so they can succeed the throne and maintain the Great Barrier. But, there is a catch. Kyoutarou is not your normal guy.
He's very strait-laced, refusing to have any sex with the princesses until he establish a relationship with them. Read as the princesses attempts to seduce Kyoutarou while he tries hard to escape from them, and as Picole-sensei lays a trap on him to bring an end to his prudishness.
Some clarification on the names. The protagonist's name is Kyoutarou Kamiku. LACEA is Laycia, Ellis is Aeris, and Merle is Meruru (I think).
What about this novel?
I say the contents are highly erotic (like over 50% of the total content per volume). Don't read if this kind of material bothers you (which I doubt you would). If you find the eroticness in the first volume stimulating, then prepare to have a nosebleed in the later volumes. It escalates as volume progresses, with each volume ecchier than the last. However, I must remind you that this is still light novel. No matter how erotic the contents are, it doesn't end with real sex. Something always happens before Kyoutarou could score the girl that interrupts them midway.
In v6, believe it or not, is the volume for