Elesantra, an adventurous elf, followed the classic adventurer career: She spent years delving into dungeons, collecting various items of power, then eventually retired very comfortably. Having developed a taste for city life, she put her money in charge of a local banker, bought a small mansion, and placed her collection of magic items in a dungeon she’d helped clear some distance away. She even hired an enterprising band of goblins to rig a series of traps and generally guard the place.
As upright and generous as Elesantra is, she has one flaw: she couldn’t stop mentioning her private dungeon at the many society parties she frequented. Fortunately, the aristocracy with which she associates know better than to steal from her; she’s far too well-known. Instead, the idea of dungeon-delving intrigued them, and they asked to see it. Surprised, Elesantra agreed and led a few friends on a tour, disarming traps and generally hamming it up. She even gave each of them a small coin once they reached her inner sanctum.
Well, that little party came back and told all their friends, and suddenly “delving” into Elesantra’s dungeon was the Thing To Do. She was quickly overwhelmed with requests, and politely declined for a few months while she redirected the goblins’ efforts. Then, she made a big announcement.
The dungeon was now open to anyone who wanted to delve into it; they didn’t need her. All the traps were now non-lethal, and the goblins instructed to lob sacks of paint instead of arrows and flee if anyone got within arm’s reach. At the end lies a “treasure room” filled with inexpensive wood and tin trinkets in the shape of swords and wands; those who reach it are expected to take only one item each.
Elesantra still keeps her actual adventuring treasure in a whole other level beneath the public one, and that one’s full of real, deadly traps.
As a friendly faction, the PCs will likely first encounter Elesantra as a source of information. She’s very well-connected among the local aristocracy, about a third of which have at least attempted her dungeon. Her elven memory allows her to remember exactly who said what to whom.
She also frequently acquires special, particularly devious traps that are built into other dungeons in the area; she will hire adventuring parties to clear out the dungeon so she can send in engineers to remove the trap, reduce its lethality, and install it in her own complex.
As a foe faction, Elesantra’s dungeon is a cover for a much more nefarious operation. She belongs to a degraded cult, which uses her actual dungeon to torture unfortunate souls into madness. The aristocratic adventuring parties above assume that the distant screams are part of the place’s ambience, faked by Elesantra.
PCs planning to stop this (or rescue a prisoner) will have to first go through the public dungeon, consisting of very simple and annoying traps: tripwires that dump sacks of flour on them, pressure plates firing darts that deal 1 HP of damage, a riddle carved into a doorway which must be opened with a key inscribed with a missing word in the riddle, and so forth. Goblins will harass the PCs from a distance (and if the PCs attack the goblins with actual martial weapons, the latter will immediately run towards the lower level and fortify it).
The treasure room contains a secret entrance downwards (and the PCs’ patron will likely have told them how to find and open it), leading into a level filled with very dangerous traps. These should be solvable but tricky and painful. Meanwhile, the goblins will keep their distance, firing ranged weapons and triggering traps where possible. These goblins are smart and have had many months to develop a defensive strategy.