Recently, a member of the 13th Age community who’s trying their hand at spell design asked if we had any resources to help with the math. We’ve written a lot about monster design, but haven’t really delved into classes; so for this month’s column, I’ll share the basic math behind figuring out how much damage characters should deal, for those of you who are creating your own character classes or variants.
Below, you’ll see the table we use when we’re figuring out roughly how much damage a spell, or an attack of a specific level, should deal. Three of the columns cover the target numbers for at-will, once per battle, and daily attacks. The last column indicates the amount of that damage that’s likely to come from the character’s ability score modifier—most attacks and spells add the ability score modifier, with a few exceptions. If it’s a normal attack that uses the ability score as a damage modifier, subtract the ability score modifier bonus from the target number to find out roughly how much damage needs to come from the dice.
A truly efficient designer would probably have created other columns, ones that show the target numbers that you’re aiming for, with just the average dice results. But I’ve always enjoyed doing the math on the fly, so today you get the columns the way I use them. No coddling!
|Character level||Target At-will damage||Target 1/battle damage||Target Daily damage||Likely ability score modifier bonus|
Multiple target math
There’s another significant piece of damage math related to attacks that have multiple targets.
If a character can make two (or three, or however many) separate attacks against any target they wish, it’s okay to simply split the damage in two (or three, or whatever)—because if the character wishes, they can focus all the damage on a single target.
But an attack that can’t be focused on a single target is different. Lots of attacks target 2, 3, 1d3, or 1d4 separate enemies. If we halved the damage of an attack that has two separate monsters as targets, that would be terrible for the player character, because what’s most important in combat is making attacks that take out enemies before they can attack you. Multiple attack rolls against separate targets do reduce the damage, but by less than you might imagine if you were spitballing. The same adjustments generally apply to damage dealt by monsters.
Here’s the math:
2 different targets (also 1d3 targets, since that averages 2): 80% normal damage
2.5 different targets (i.e., 1d4 targets, use it all the time): 75% normal damage
3 different targets: 70% normal damage
3.5 different targets (i.e.,. 1d6 targets): 65% normal damage
4 different targets: 60% normal damage
5 different targets: 50% normal damage
…And so on, though I can’t remember many cases of “and so on” coming up!
I hope this is helpful as you design new powers for 13th Age heroes. With another Bestiary on the way, they’ll need them!