As in many of my previous posts, I am building on the work of others. In this case I am going to be taking something which Zak Saban over at Playing D&D With Pornstars did and monkeying around with it just enough to make it work for me and my megadungeon. This post, which includes a quick little DMing tool: Megedungeon Key Mechanic, is great.
Let's set the scene:
The party of "brave" adventurers has just slain the massive, bloated Rat-King, Pubus Byle. From his coffers they liberate dozens of interesting items as well as a small fortune in gold coins. One of the items is a tarnished iron ring, on it hang eight mismatched keys: the keys run the gambit from simple brass skeleton keys to golden, jewel encrusted master-pieces.
Which doors do the keys open? The players do not know... but more imprtantly, the DM does not know either.
When a key is found, roll a d100 and assign the resultant number to the key. So now the party has key 37. When the party comes to a door, a rogue (maybe?) inspects the door, and reaches into his purse, drawing out the iron key ring. He takess key 37 and inserts it into the lock. The DM rolls a d100. If the roll is less than the key's number, the key fits.
Great! Simple and fast to execute. It keeps the DM from having to prep ahead for things that may never happen. Not much book keeping. In fact no book keeping is required until a key gets a match and the room-key combination (the key's number) is marked on the megadungeon map.
I have decided to have this mechanic do more than just tell me whether key X fits door X. As I have been developing the campaign outline and map of Saedom (my tent pole megadungeon), I have discovered a need to assign locations and entrances to my sub-levels. By sub-levels, I mean premapped micro-dungeons which can be inserted, as modular pieces, into the megadungeon at any location; e.g. a large crypt complex which has been uncovered by a recent cave which has blocked one tunnel while opening up a new tunnel. Sub-levels are kind of like detours which take you to awesome places... like stopping at the Corn Palace as you drive through South Dakota... could South Dakota be considered a sub-level of America? I have eight sub-levels which have already been completed. I will tag them at the top end of the d100 spectrum when rolling for room-key combinations. So, if the room-key roll results in a 99 the portal will connect them with sub-level B: The Tomb of the Last King. That door will be known as 99B; door-key combination 99 connecting to sub-level B.
The Geomorphs Have Just Leveled Up!