The rules governing the interaction between Dark Lords and Adventurers have been established for a long time, but never really written down. Like the laws associated with economics and physics, they don't change much but gradually become more formalized.
The general rules of thumb are:
1) Build an imposing but not unbeatable fortress somewhere foreboding.
2) Stock it with something of great value i.e. treasure, magic swords, captive princesses etc etc.
3) Get the word out that you've got something worth stealing
4) Sit back and wait for the rush of would be heroes trying to take it from you.
Pretty simple, really.
Of course getting the word out is the most challenging part. It's why Rule #4 exists: Always Leave Survivors. Those who have escaped the butchery of their party make the best PR men and have the added bonus that you don't have to pay them. Simply let them live and they will spill their story in every alehouse and tavern from here to whatever forlorn shithole they crawled out of.
You have to be prepared to move with the times, a great Dark Lord is nature's most adaptable creature. Instead of being the destination, I've chosen to be the entire fucking journey. Whether they are aware of it or not, most of the adventurer parties that seek out my Evil Strongholds™ are in fact driven there by my network of intertwined Retail, Entertainment and Public Relations divisions acting upon a proven business model.
There are ATA's, or Adventure Travel Agencies in most of the major cities on this world which cater exclusively to up and coming campaigners looking to strike it rich and make a name for themselves. I should know, I invented them.
For a modest fee my ATA, Sword and Staff Sojourns™ will book a trip for your group of erstwhile heroes to my nearest Malevolent Fortress™ with a range of available travel and support packages. Anything from a couple of mules and a native guide, to a 4,000 square foot silk and wool palace that comes with it's own butler, armorer, executive chef, masseuse, healer, concubines and set up/break down crew.
Choose your own comfort level.
This is why I build in godforsaken wastelands, ideally I want my stronghold to be at least a fortnight's hard travel from the nearest town. And the 'nearest town' is a always a nice little village with an unusually fine selection of merchants and armorers for such an out of the way place. I've worked hard to ensure that this is so.
You see in the old days an Evil Bastard might make some kind of arrangement to sell the equipment, magic items and weapons of slain freebooters back to the merchants of the nearest village, but today's Dark Lord owns the whole town. Established it in fact. Nowadays my business model consists of setting up a remote village trading post before I even begin development of my next Foul Citadel™.
I employee a large troupe of mobile craftsmen, taveners, merchants and actors that with but a week's notice can produce a rustic looking village to service the influx of sword-weenies and spell-twats that will descend upon my newly completed Citadel.
They're like locusts or cockroaches that leave money behind when you kill them.
This whole economic premise relies on the colossal arrogance of your average adventurer and I am never disappointed. Tell your classic spear-cunt and wand-fag about a particularly lethal dungeon maze and they will fall all over themselves trying to die in it regardless of their experience level.
It makes me laugh. It makes me money. It makes my murdered Father proud of his son/assassin.
Tune in next time when I discuss the Rules of Dark Lording.
Yours in foulness,
The Dark Lord
His Law Be Word Unto Thine Mother
