Tunnels and Trolls: What is an Average Character?

The question of, "what is an average character for T&T?" comes up in my mind because I need it to balance encounters. Remember, the formula for monster rating is:

MR Attack Roll = (MR/10)d6 + (MR/2) adds

So a MR of 50 nets a 5d6 + 25 combat roll (at full strength). Now the question is, what is an even fight? The answer is a character with an attack roll of 5d6 + 25. That would be a character with a 5d6 longsword with the following attributes:

STR: 20
CON: 20
DEX: 19
SPD: 16
LK: 18
IQ: 10
WIZ: 10
adds: +25

But wait, if this is an version 8.0 warrior, they will get an extra 2d6 for their warrior bonus (at level 2), but for a rogue this would work. For a level 2 warrior, we would need to knock an average of 7 points off STR, DEX, SPD, and LK to get that magic +25 to adds with that 2d6, so I would say something like this:

STR: 20
CON: 20
DEX: 16
SPD: 16
LK: 14
IQ: 10
WIZ: 10
adds: +18 (+2d6 warrior bonus)

So this is a "good build" for a level 2 character. You may have noticed I kept the warrior's STR and CON the same, and the other attributes that contribute to personal adds are 60-80% of the character's highest score, let's say 75%. Stats that aren't important for the character, in this case WIZ and INT, are left at a value of 10.

Parties

Now for parties, you will be totaling up the entire damage output for the group and pitting that against a monster with a significantly higher MR. Let's say your party was five of the above characters, three warriors, a rogue, and a mage. Even though rogues and mages don't have the warrior's bonus dice, you could use the warrior's numbers because mages and rogues have magic that is a significant adder to damage per turn. So let's say our party comes out to about this:

25d6 + 125 or an average of 213 points of damage

RPG Algebra!

So now what? Algebra, that's what. We need a formula that tells us, given a party's average damage output, what is an MR that gives them an equal challenge?

213 = (MR/10 + 1) * 3.5) + (MR/2)
213 = ((MR * 0.35) + 3.5) + (MR/2)
213 - 3.5 = (MR * 0.35) + (MR * 0.5) - 3.5
209.5 = (MR * 0.85)
209.5 / 0.85 = (MR * 0.85) / 0.85
246.47 = MR

And, a MR of 246 is 25d6 + 123 (average damage 211), so bingo, we have our formula! Let's 1/x this "minus 3.5 and divide by 0.85" thing and get something we can multiply by, okay? Who ever said you wouldn't use algebra in real life? Seriously, you can solve a lot of your life's problems with a little math. So we have this magical formula:

50-50 challenge MR = (average party damage - 3.5) x 1.174

Let's test this! A party that does 15d6 + 25? Average damage is 78, so the MR would be 78 x 1.174 = 88. A MR of 88 does 9d6 + 44 damage, or an average of...76. It comes out very close. Let's try a party that does 30d6 + 400, or 505 points of damage on average. MR is 590, or 60d6 + 295, or an average of 505 points of damage from the monster's side.

This is a formula you can use on the fly while the party is inside the dungeon. Simply throw some easy fights at the group, secretly write down some of the total damage outputs during the combat, and multiply up to get a good 50-50 fight for the next room. You can modify the MR up or down 10-20% to make it a little harder or easier, but remember a 50-50 fight means the players will lose the battle 50% of the time just given straight dice rolls - so this will be a tough fight.

One of the beautiful things about this formula is that no matter what house rules you are using, no matter what level the party is or how many people they have, it adapts as long as the dice and adds formula for MR is not changed. If you give your warriors more or less adds, your party doesn't use a lot of damaging magic, or you have custom spells that do special damages - all you need to know is average party DPS (which you can get in the first few turns of battle) and the formula works.

It is also simpler and more exact than D&D's CR system, since this is real math and hardcore statistics. Subsequently, this system is also a lot more harsh and unforgiving.

Don't Adjust Too Far!

Also remember the bell curve. You don't want to push encounters too far away from the midpoint, because let's say you set MR to 50% of the calculated value for a simple fight. For our example, that is a MR of 46 for 4d6 + 23, or an average of 37 points of damage. If the party is doing 78 points a turn, that is a difference of 78 - 37 = 41 points, and there is no way 4d6 will ever let that monster to roll higher than the party. You might as well forget about this fight unless it is a one-on-one with a single person.

Let's lower the MR by 10% to 83. That is 8d6 + 43 for an average of 71 points of damage. A 71 to 78 fight with 8d6 damage is good, it gives the players an edge while still letting the monsters possibly getting a hit or two in.

If I were to err, I would err on the side of 10 or 20% higher MR, because remember as a monster takes damage, the monster's adds from their MR drops (but not their dice). After a few hits, those adds will drop our critter below the party's average damage and change the tide of battle. You may want the fight to start off with the party taking damage, the party begin clever through a spell or stunt, and then the party gaining the advantage after the monster takes a couple hits.

Have Armor? Increase MR!

If the party has a lot of armor you may want to go 30% or 40% above the rated MR just so the monster's damage output can blow through that armor and get some hits in. Do A 50-50 combat encounter once and then decide if the party took it on the chin or they took it on the helmet, and then decide from there.

The 50-50 number only applies on the first combat turn, and it says who will take damage first. As the battle goes on, one side will fall. But sometimes, the side that gets damage in gets an immediate advantage, and you may want that to be the monsters to put the party back on their heels a step in order to get some crafty play going.

Craftiness is a Player's Right

It is an important point, since this formula does not take into account crafty players who will make stunt SRs, use spells to take foes out of the fight, and use other clever tactics to weaken the enemy. But that is the players' right and part of the fun of the game. In a first-turn 50-50 fight they will need to be clever to win, and this fight may drain a good amount of their resources, so this is a good tool to use to judge encounter difficulty during play.

If a party wins an unfair fight through wits and cool stunts, that is a very good thing, and a memorable moment. If it is too unfair, it is un-fun. If it is too easy, it is also un-fun. So you want to be able to find that middle spot for MR, and know if your players can defeat that with ease, or they have trouble with that battle. Your players may be so good you may multiple party damage by a higher factor, such as 1.3, in order to determine a challenging MR for them.

It depends on the party, the players, the house-rules, the gear, and a lot of other stuff - but it all ends up in a number you can write down and use to build the next challenge for them. If MR 92 was a blow out and these players are good, maybe behind that next door is a MR 122 ogre, and the party finds itself knuckling down and getting clever to push this brute over and grab that sack full of silver coins.

EDIT: Slight math fix to the formula to account for MR 10-19 = 2d6 instead of 1d6 (MR/10+1 = dice).