Board Thread:General Discussion/@comment-38565009-20200610212457/@comment-27013478-20200611131058

It's a series of books, along with one doujin. There are also fan novels and doujins, endorsed by the author. Book 1. https://monstergirlencyclopedia.fandom.com/wiki/Monster_Girl_Encyclopedia_I Book 2. https://monstergirlencyclopedia.fandom.com/wiki/Monster_Girl_Encyclopedia_II

And other main books. https://monstergirlencyclopedia.fandom.com/wiki/Monster_Girl_Encyclopedia_World_Guide_I:_Fallen_Maidens https://monstergirlencyclopedia.fandom.com/wiki/Monster_Girl_Encyclopedia_World_Guide_II:_Demon_Realm_Traveller%27s_Guide https://monstergirlencyclopedia.fandom.com/wiki/Monster_Girl_Encyclopedia_World_Guide_III:_Sabbath_Grimoire https://monstergirlencyclopedia.fandom.com/wiki/Succubus_Notebook