Harem Sister follows Hilcruz, son of Hilmedes from Harem Castle, as a church shelters him and he plots his revenge against the Ishtar Kingdom.

The young boy Felix, who admires the Kingdom’s Knights, is suddenly on a certain day set up as the Kingdom’s crown prince, unanticipating that he would live a life immersed in s*x. There is a queen who is also a mother, there are maids, and an ex-boss female knight, but other cougars approach! The innocent boy’s reasoning is on the brink of destruction.... more>>

With over 50 books at this point, the Harem Series is by far the longest 18+ LN series out there. Most of the novels aren’t directly connected, but they all take place in the same fantasy world.

For now, let’s take a look at very first entry in the series: Harem Castle (ハーレムキャッスル). <<less