Deep Druids, pt. 3: XP Math

Adventure’s coming together. Got some nice map art. We’ll get to that stuff later, but first: experience points!

I’m going to explain the weird twists and turns you have to get yourself into if you want to do any type of precision XP allotment. By the end of this post, you’ll understand why so many WotC adventures just say “when the characters reach the attic, level them up to level 2.”

Say you want a dungeon that takes characters from level 1 to level 2. A goblin dungeon. A single character needs 300 XP to level up. So we’ll assume five characters total, which makes 1500 XP in our dungeon. So far so good. That’s 30 goblins, right? Well.. not quite.

First of all, you don’t want 30 rooms with one goblin each. Those encounters are too easy. Nor do you want all goblins piled up in a single cavern – that’s far too deadly. What you want is a healthy mix of easy to deadly encounters, with an emphasis on medium and hard. Something like this:

I’ve added the average XP value next to the difficulties. There’s a bit of room, of course. An easy encounter is somewhere between 125 XP and 250 XP, for instance.

Next, you’ll want a good number of rooms in your dungeon. Especially when writing something for publication there is a minimum and maximum to this number. But even when not, you’ll want to stick to the DMG’s guidelines for leveling speed. Reaching level 2 should take a single session, according to those. How many rooms can a party get through in one session? Well Death House took me 3 sessions and that thing’s got 40, but my players skipped a good chunk of the basement. Let’s cast a wide net and say you could do 5-10 rooms in a session.

Of course, not every room is a fight. The DMG has some suggestions with its Random Dungeon appendix. Half the rooms have monsters in them.

So now we have 3-5 fights in our level 1 dungeon. But we also want a good mix of difficulties, so maybe something like 1 easy, 2 medium, 1 hard, 1 deadly for the 10-room dungeon. That’s ~1800 XP. Nice! We could drop one medium encounter to make it a smooth 1500 – but we’ll need that extra XP.

Because here’s where 5e complicates matters. The XP value of a fight, which determines its difficulty, is not equal to the XP gained by winning the fight. This is because of the dreaded group modifier! A pair of goblins is worth 100 XP, but its difficulty level is 150 XP. So unless we stock our dungeon with single monsters, the characters will gain less XP than the encounters would suggest! Here’s what the actual XP values are for our difficulty levels:

Now we need to pick one for each row and make sure the total hits 1500. And also ensure that our dungeon isn’t boring, so ideally we have a mix of different encounter sizes.

Here’s a stab at it:

Total: 1445 XP

The way to get to a solution here is to just start everything on “1 monster”, and move individual entries further down the “more monsters” line to decrease the total XP until you hit something close to the target (if “1 monster” down the line doesn’t give you enough XP off the bat then it’s time to go back to the drawing board).

We’ve strayed quite far from dropping 30 goblins in our cave! In fact, we’ve now locked ourselves into very specific combat scenarios. A single deadly boss monster, a pair of easy monsters, a single medium one, etc. The next puzzle is to find the correct type of monsters for each of these encounters. This too is a bit of a puzzle, better get those Monster Manuals ready!

Total: 1250 XP

As a first attempt, we’re now down 250 XP, which is not too bad but it does mean that a 5-man party will just miss that level up. Some encounters also changed in difficulty, most notably the ogre boss (there’s just no single monster worth 560 XP). Time to start playing with those dials! In this case, let’s add one more encounter with four regular old goblins worth 200 XP. We’ve got a convenient “hard” slot leftover anyway. That’s still 50 down, so let’s say the ogre boss has a fearsome helmet and steel leg guards that increase its AC by 2, and its XP value up to 500.

So now we have our final roster:

Room 1. 1 goblin + 1 worg.

Room 2. 3 goblins

Room 3. 1 brown bear

Room 4. 1 bugbear + 1 thug

Room 5. 4 goblins

Room 6. 1 ogre

Room 7-10. No combat here, but a mix of treasure, traps, tricks, etc.

You can kind of see the dungeon taking form in your mind’s eye. The mounted goblin guards the entrance. The brown bear is a “neighbor” that the goblins use as a natural deterrent. The bugbear is the brains behind the operation, using the ogre as an enforcer. Perhaps the thug is an “ambassador” from the local bandit operation?

It works but man is this a lot of work! I wonder if the Dungeon of the Mad Mage crowd went through this exercise… In a normal game, you’d just create Easy-Deadly encounters, put them in rooms, and let the players level naturally, but for a megadungeon like this, you want to make sure the XP per level is within expected bounds. As I am trying to do with the Grove – it’s designed to be the size of half a regular DotMM level.

Speaking of which, here’s the roster for the Grove of the Deep Druids:

Total: 25300 XP