ベルゼバブＣ

An insect type monster that was sealed in ancient times by the first Monster Lord. An ancient monster that belongs to a different evolutionary tree of monsters, different from the current generation. An incredibly powerful monster, she was revered as a God in ancient times. Many were sealed at first, but the vast majority have died over the years. Only three of the strongest have managed to survive to the present day. Their strength is formidable, but it’s their reproductive ability that is truly terrifying. Mating with a single man for a year straight, they can give birth to 10,000 daughters. Keeping the man as a reproductive tool, she keeps his penis in her abdomen, keeping them in a trance of pleasure to ensure continual insemination. Inserting the eggs into the man’s rectum after fertilization, he is treated as nothing but a reproductive tool. [From In-game Monsterpedia]