Girtablilu

Encyclopedia Entry:
A kind of arachne that lives in the desert. Its lower body resembles that of a scorpion, and it has a giant poison stinger on its tail. It is called “the assassin of the desert.”   Even among the monsters that live in the desert region, it is especially violent and dangerous.

When they find a man that strikes their fancy, just as their name “assassin” would suggest, they approach the man without making a sound and swiftly stab the stinger into him to inject him with poison. Out of all the monsters, the poison they possess is by far the most potent. It is an instant poison that causes paralysis immediately upon entry into the bloodstream, plus it attacks the entire body with heat, especially the lower body. Furthermore, it causes a man’s body to produce a high volume of semen. No matter what the man’s will, his penis will get hard and swollen.

With the man paralyzed, they take him back to their own dwelling and continue to forcibly have intercourse to bear young. Since they continuously inject a man with poison during sex, he never runs out of semen during the whole act, and neither will he lose his erection. Because of that, they likely won’t stop mating until either she becomes satisfied, or he passes out. Furthermore, they are very sadistic in nature; since they get such pleasure out of it, they’ll probably keep fiercely injecting the man with poison during sex even if he is willing. Also, how much their sadistic nature reveals itself is proportional to how much they actually care about the man they’re with. So when they’re with a man they like, they start frequently stabbing him with the stinger as an “expression of affection,” and will probably end up mating with him more frequently and furiously.

As for the body of a man who's been frequently injected with their poison, eventually even his nerves will be violated and changed by the venom. Being pierced by the stinger and injected with poison will end up being processed by him as pleasure rather than pain.

Also, even though they are called “assassins,” in the same way as other monsters, they won’t actually take a person’s life. No one ever dies from their poison. But a man caught by one of them cannot easily escape, so it’s certainly difficult for him to ever return alive to the human settlements.