Deep in the deserts, in the lonely places that attract only madmen and adventurers, we find the Lamia. These half-woman, half-lion fiends come from one of the most primal monster breeding grounds in human imagination: the terror of the things that live beyond the map and the unknown that lays in wait out there.

There is physical danger in the unknown lands, of course. Your Players could go to one of these ruined desert temples and fall afoul of a trap or the crumbling ruins themselves. Or, if you’re of a particular breed of DM, hunger and thirst might do them in.

The danger that the Lamia represent, however, isn’t the physical. It is the danger of a loss of agency, because the Lamia are very, very good at finding out what you want, and making sure you know they’re the only ones who can get it for you. This puts them in a similar position to Harpies, actually. They cloud the heart and tug on the heartstrings of desire. The main difference is that Lamias are more solitary than Harpies are, and can rely more on the manipulation of the senses rather than the manipulation of the mind.

Let’s start with what the Lamia can actually do.

Their three great skills are Deception, Insight, and Stealth, which should tell you a lot right away. These aren’t Sphinxes, who sit in front of their temples, waiting for hapless Adventurers to show up. The Lamia lay in wait. They stalk their prey for a while, watching them. Listening to their conversations and reading their interactions so that they can later pull on the delicate threads that bind them together. And if they sense some intra-Party conflict? Perhaps your Paladin is not happy with how the Rogue keeps looting temples. Or the Druid doesn’t like the Wizard casting Fireball in sacred groves. This is information the Lamia might be able to use when she finally makes herself known.

And with the ability to cast Disguise Self at will, she doesn’t have to show up as a large lion-centaur. She can appear… however she wants, since she has an exception to the usual Disguise Self rule and can show up as a medium biped. Approach your Party, start gaining their trust. Perhaps she’s lost her way from a desert caravan. Maybe she’s an explorer herself, looking for the same hidden temple. Either way, she’s going to try to exploit the Party’s desires and needs in order to make herself invaluable to them.

That is how, ultimately, she gets what she wants.

Interestingly enough, there’s an overlap here with Hags as well. Lamia aren’t interested in fighting – they’d much rather cajole, bargain, and deceive. If the Lamia has to fight, then something has already gone wrong.

But what does the Lamia want with your Adventurers? The Harpies want to eat them, the Hags want to ruin them – there must be something that the Lamia are looking to gain from the people they find all the way where the maps end.

Fortunately, the 2024 Monster Manual has you covered, with a table of possible “Lamia Pacts.” These are things such as, “bring it a possession from a ruler or a noble,” or “place a strange idol in a specific site or home,” or “slay a monster and retrieve a specific organ” to name a few. And these alone should tell you how Lamia are different from Hags and Harpies: Lamia want servants.

Her motivation for servants can be whatever you want them to be, of course. Perhaps she wants praise and adoration, and your Party’s job is to kidnap a particularly attractive human and bring them to her so she may keep them like a sculpture in a gallery. And so now your Players need to infiltrate a specific desert caravan, find some way to separate this person from their family and friends, and deliver them so that the Lamia can tell them the precise combination of tiles that they will need to press in the hidden temple to disarm the ancient traps.

Perhaps she wants to accumulate power. Out here, on the edges of the world, it’s important to build a base of power to keep oneself safe, as there might be greater terrors out there in the unknown. The Lamia may ask your Players to bring her an item of great power – a weapon or a ring or a staff – that she can use to secure her position. She may send some of her Jackalwere servants with them to assist, or to simply watch and make sure they’re not plotting behind her back. With the delivery of the treasure she seeks, and the security it brings, she may then tell your Players how they might find the ancient outpost where the Archlich of the Sands is said to keep her phylactery.

Or she may not. You could play the Lamia as an opponent who keeps asking for more and more, and keeps widening the cracks in the Party to get it. She even has access to the Geas spell, which she may be able to wrap in a haunting story of shifting sands and lonely oases until it’s too late for your Players to know what’s happened. One failed Wisdom save and they are the servant of the Lamia for thirty days. And that is a long time for this monster to get her hooks into someone.

At first, of course, her demands will seem perfectly reasonable. After all, what Adventuring Party isn’t willing to slay a monster or steal something? But her demands just keep getting a little more…. challenging. First you steal an item that doesn’t belong to you. Okay, illegal, but not that bad.

Then she asks you to kidnap someone.

Then she asks you to betray an ally.

Each time, it becomes harder to walk away. Not just because she’s dangling something the Party wants just beyond their reach, but because they’ve already agreed to do so much already for her. What’s one more thing? You’ve already done so many questionable things. If you stop now, what was it all for? Eventually the Party is not just working for the Lamia: they’re dependent on her. More than they need her to give them the map to the Crystal Illuminarium, they need her to tell them that they’re doing the right thing.

To justify the terrible things they’re doing in her name.

If, ultimately, your Players become tied to the Lamia, then you can start to explore the problems of desire, and learning what you’re willing to surrender in order to get what you want. The Lamia is a master of this. Your Players came into the desert looking for something, and what they found was a path that led inevitably to her.

One perfectly reasonable decision at a time.