Keeping players engaged in a dungeon exploration can be difficult beyond its basic premise: they are knocking down a series of doors in an impossibly deep and large underground facility.
But that’s not the real reason why progress in such a dungeon seems to crawl. It’s that it is difficult to maintain engagement when evil’s aims do not seem to pose an immediate threat.
In fact, it’s relatively easy to keep players’ interest when the bad guys want to assassinate a local civic leader or the PCs are rooting out spies in their hometown against a likely invasion. Or better yet, a family member needs their help with a bully, thug or overbearing noble.
It’s a much harder task when on the 16th level of the grand dark halls the adventurers encounter third-generation descendants of a cabal bent on releasing the cosmic doombringers, but only after they acquire an ancient tome hidden in a secret antechamber.
“Yeah, good luck with your evil whatchamacallit. We’re going topside to hang out at a tavern.”
It’s a natural problem. Evildoers residing deep in the megadungeon are so far removed from the characters’ own lives, their foul plans don’t register.
What is Halaster up to in Undermountain anyway? Why should the PCs even care when something comparatively nearby seems far more enticing: the Cassalanters have another scheme to defraud Waterdeep of its riches and the PCs already have four invitations to the Cassalanter masked ball. It doesn’t matter that the Cassalanters wouldn’t last a minute against Halaster’s lowliest minions; the Cassalanters are having a party!
Well, the thing is, Halaster’s having a party too. But it’s not framed that way. Whether you are taking a group through Castle Greyhawk or the Mad Wizard’s many dooms, look for ways to present the threats so they resonate with the players — give them a chance to see why they are dedicated to this enterprise of exploring long, dark halls.
>Make the Villain matter. Whoever the big bad is on a given level, give them a history with a patron or faction that matters to the PCs. Not only is the villain trying to raise unspeakable horrors, he also had our society’s most precious possession!
> Make the Scheme matter. Yes, yes, animated dead drow and troglodytes are bad. But they aren’t just going to be roaming around in the dark halls. They’re being unleashed on the surface!
> Evil has a long reach. If the old priest releases the demon from its gemstone prison, it’s going to affect more folks than just those in the Maze chambers. Demon cultists in the city and in the region are going to be emboldened too!
> Bubbling up and slithering out. Whatever breaks free or is loosed from the 21st level has one goal — rising to the surface to overthrow the rulers and supplant itself on the throne.
> Doorway elsewhere. The real danger is far, far away. But there is a secret gate in the bowels of the dungeon. Time is of the essence. Brave the dangers of the dark deep to gain access to the gate so your real adventure can begin.
The trick is sinking these hooks in: Using NPC patrons and other associates to remind the PCs of their bonds and loyalties and using those elements present on the character sheet to bolster their interest in the enterprise. Drawing a knot on these connective threads and drawing them tight are a key way to revive interest when it flags.