A madman's riddle
Nothing in DCSS makes sense, if examined closely. I don't mean just because it's a video game. For example, Castle of the Wind had a more realistic sense of the passage of time. Many modern survival games simulate realism to an obnoxious degree.
My point is that DCSS' unrealism breaks immersion and inhibits player imagination of a plausible plot. This ultimately reduces enjoyability and replayability.
I've tried repeatedly to design a solution to this problem, with middling success. Not until many months after I dropped DCSS did I arrive at the answer. I daresay it is the only viable answer.
Oftentimes it is not finding the right answer that is difficult, but asking the right question. In this case, the right question is: "What god could possibly be responsible for this ridiculous insanity?"
The question answers itself: Xom.
I feel I could end the essay here, and it would be a good mic drop. But I have further thoughts!
God is not mocked
Only Xom creates trick altars of other gods. He has no respect for the rest of the pantheon. His power exceeds theirs, limited only by his madness.
Usually, this limit is enough.
Dungeons are naturally occurring sentient gems. The Dungeon is the oldest Dungeon on Terra. Empires rose and fell from farming its riches. Heroes and villains gained their powers within its depths. The Dungeon contracted with all the gods and demons, save Xom, who cannot be trusted. But Xom delights in overthrowing kings. And so he found a way into the King of Dungeons, cracking its crystal mind.
Now the Dungeon has forgotten the ancient treaty between mortal and dungeonkind, that allowed the two to prosper in symbiosis. It exerts its mental domination over all who enter, slowly converting them into mindless minions, doomed to eternal respawn.
Xom's contagious madness has amplified the Dungeon's psychic domination, letting it seep up through the subconscious of even the strongest minds. Through its seals scattered through the seven planes, the Dungeon has subverted and stupified the seal guardians and their courts. Xom's madness infects the fabric of reality itself, threatening a chaos deeper than Lugonu's Abyss.
Why so few crawlers? Because Xom resets entrants to level 1 when they enter. He also confiscates almost all their equipment, in exchange for a starting kit.
Crawlers can exit the dungeon freely — at the cost of their sanity. They become raving lunatics, Xom's biggest fans. Life thereafter is nasty, brutish and short.
Inside the dungeon, reality warps, becoming gamified, cartoonish — all for Xom's amusement.
The other gods are not amused. In retaliation, they seed Terra with divine artifacts, to equip champions to counter Xom's curse.
Of course, nothing is free.
The player has obtained a cursed artifact, the Charmless Bag of Holding. It cannot be removed. It transforms any pocket into a spatial storage portal for 52 slots. It also lowers charisma, making most people hostile. Lastly, it confers immunity to charm — including Dungeon domination.
Nobody wants to kill a cursed champion, since the curse jumps to the killer. The player is speedily ushered on his way.
The gods have promised to remove the curse on the artifact of whoever removes the Dungeon's core, thereby killing it. Whoever possesses the core may also plant a new dungeon, becoming its immortal keeper.
You have nothing to lose, so you enter the Dungeon… from which no sane creature has ever returned.