The End of the Campaign

After two years, my latest campaign, "The Eberron Code", has come to an end. The final session centred around a showdown between the 15th level PCs and the demon Bel Shalor. If successful, the PCs would bind the demon far more tightly within the Silver Flame, preventing its corrosive influence, and thus cleansing the Flame (and the attendant religion). If they failed, they risked the existence of their very souls, and would die unremembered.

This was not very dissimilar to the end I had envisaged before starting the campaign, and was the final act in a story that had played out in a very satisfactory manner. Naturally, I had visions of it playing out as an epic battle, going first one way or another, and ending with the PCs victorious, but counting a heavy cost.

Just one problem with that: high-level D&D 3e doesn't really lend itself to that sort of a battle. The demon in question had several "save or die" abilities, while at least one of the PCs was able to muster equivalently powerful abilities. It was entirely possible that the battle might be over in a small handful of rounds, with either the enemy being one-shotted (and so a horrible anti-climax), or with the PCs falling far too quickly (thus being very unsatisfactory).

So, I was a little worried going into that last session. After all, two years' of work was on the line, and if this went wrong then there was no coming back from it.

Well, in the end the session played out extremely well. The Wizard tried his cunning trick, offering the demon the "Book of Vile Darkness"... a tome on which he had placed a trap the soul spell to capture the beast. Unfortunately, although he tricked the demon, he also tricked the NPC allies, who proceeded to get in the way. And in giving them the heads-up, they accidentally tipped off the demon.

From there, we proceeded with an epic battle. For a long time, the PCs found it hard to do any damage to the beast, but they were gradually making headway. Bel Shalor focussed his attacks on the NPC allies first, clearing the field of those who had opposed him first. Then, he turned his attention to the PCs. Still, about a quarter of the required damage was done.

At this point, the vorpal blade went snicker-snack! And Avon Blurric, the PC wizard, fell dead, his head severed from his body. Which was interesting, to say the least.

The balance of the combat was thus turned, with the PC cleric, Harrington Fargo, scrambling to reunite the Wizard's head and his body - for he had access to a powerful magic that could restore the newly-dead to life! Meanwhile, the Ranger, the Rogue, and the Artificer kept the demon busy.

The PCs had now found the technique for doing some serious damage to the demon. Garret the Green, the Rogue, was doing 8d6 damage with each sneak attack, and was scoring roughly one hit per round. The others were contributing a few points here and there. And eventually, Craetegus (the Ranger) was able to sever the creature's wings, denying it the ability to fly.

Bel Shalor responded with his most potent ability, the dread implosion spell. And Craetegus was no more.

But the tide now turned once more. Restored to life, Avon made use of his staff of frost to blast the demon, while Garret continued his sneak attacks. And finally, after three hours of play, the demon was felled. All that remained was to finish it off. Avon, Harrington, and Mondo (the Artificer) retreated to safety at this point. Garret finished the demon, relying on his preternatural reflexes to save him from the resulting explosion.

And that was it. The campaign was done.

There was then a brief epilogue, as the survivors returned to the world, as they progressed on to further adventures or a well-deserved retirement, and as the results of their victory became known.

The end.

My overwhelming feeling at the end of the campaign was exhaustion. So much had gone into that last session, and so much had been depending on it, that when it was done there was a sudden relief, and tiredness. But once that had passed, there was a great satisfaction - the last session had indeed lived up to the rest of the campaign, and had gone down just about as well as could be hoped. Indeed, the result was pretty much exactly what was hoped - a narrow victory, and a high cost.

So... time for the next campaign!

(In seriousness, the next campaign doesn't start for several months, and won't be anything like as elaborate. I also have quite a few bits of "wash-up" to do for this campaign, which I'll be posting in the next little while. So it may be some time before I start thinking in earnest about "Imperial Fist".)

About Dice Rings

Over on the Falkirk RPG website, there was a brief debate about "Dice Rings". These, as the name implies, are rings that can serve as dice - they have a fixed inner ring and a loose outer ring marked with numbers. To roll a random number, you spin the outer ring, and when it comes to a halt there's a read-out point at which you get your number.

My contention is that these dice rings are a neat gimmick, but that I would very much doubt the randomness of the dice. In particular, it is my contention that the result is coupled to the initial state of the ring.

Now, it was noted on the original kickstarter that the dice have been extensively tested for randomness. And this website provides more details about their testing.

Firstly, to ensure that the dice can't be 'aimed' or otherwise cheated, the numbers around the ring have been placed in a carefully-selected order. Where possible, the numbers alternate between odd and even values and between high and low results. And while '1' and '20' aren't directly opposite one another, they are close to being opposites.

Secondly, the creator tested the dice by spinning them over and over, recording the results, and checking there were no anomalies - that each result came up as often as any other.

So that's it, right?

Actually, no.

Consider this: suppose your PC is having a hard time of it. You've got three attacks per round, but you need a nat '20' to hit. You've just rolled one such '20', and are now rolling your second attack (or rolling to confirm the crit). Either way, you spin the dice...

Now, in this scenario, it doesn't matter that the dice have been checked to ensure that, on average, they roll each number as often as any other. And it also doesn't matter that you have a 50% chance of an 11 or more, or a 50/50 chance of an odd or even number.

What matters is that on this roll, the odds of scoring that natural '20' need to be exactly 5%. No more, no less.

Obviously, the order of the numbers around the ring does nothing for this - whatever order is chosen you'll still need the ring to spin through exactly N revolutions, where N is an integer. But what about the testing described in "secondly", above?

Well, here's the thing: the test that he describes is effectively a "Chi Square" test, which can indeed be used to test a die for randomness. The problem is, though, that many pseudo-random generators would also pass such a test. (Indeed, if you had a generator that simply stepped from '1' to '2' to '3', up to '20' and then to '1', it would still pass that test. Although in that case, the uniformity of the results would itself be a warning sign.) To be sure the outcome wasn't tied to the initial state, you would need to run this test 20 times - once for each of the initial states of the ring.

My expected behaviour of the spin ring is as follows: each person will operate slightly differently, but each will naturally adopt a favoured technique for spinning the ring. This technique will cause the outer part to spin through X revolutions (where X is not necessarily an integer), plus or minus Y.

Now, Y may very well be more than a full revolution of the ring. So, that's good enough, isn't it?

Again, I'm afraid the answer is "no". Because the distribution of values won't be even - like virtually everything else in the sphere of human endeavour, it will sit on a bell curve - the most likely single outcome will be for a spin of exactly X reolutions, then the next most likely will be one position to either side, and then the next position outwards, and so on.

This means that, depending on the initial position of the ring, the outcomes will themselves have a bell curve distribution, not the even distribution that is required. The most likely outcomes will vary, but will depend on the initial state of the die.

And, for that PC who needs a natural '20', the odds of actually scoring that value are unlikely to be exactly 5%. Sorry, your character's dead.

Now, all that said - three more things.

Firstly, as the designer notes, these "spin rings" are based on something called "worry rings", which are sometimes suggested as a means to cure anxiety - the wearer fiddles with them mindlessly, in order to distract his mind from his worries. I would expect spin rings to work extremely well for such a person - by constantly fiddling, they'll effectively be pre-randomising the starting position of the ring, and so give a random aspect (much like a well shuffled deck of cards). They would, however, need to do this every time between rolls, or they'll still never confirm that crit. (Conversely, it's likely the rings would work especially badly for someone such as myself, who tends towards reducing entropy by regimenting my dice.)

Secondly, it is by no means guaranteed that any particular die is properly random anyway. Indeed, depending on how much faith you put in the Gamescience presentation, it appears likely that most dice aren't properly random. In which case, little is lost by switching to spin rings - you're moving from one imperfect method to another.

Thirdly... if you really want to use a spin ring in favour of a d20 in one of my games, I won't stop you. I find the topic interesting, but mostly for the theoretical exercise in reasoning. When it comes to actual practice, I really don't care all that much.