Laws of (Pretend) Inheritance!

One of the coolest things about the Pendragon RPG is the emphasis on generational play, spanning more than one lifetime. This epic scale is something I also really love about Paradox Interactive’s Crusader Kings series.

So while I was out hiking the other day, I thought up a quick and fun way to start a dynasty for your RPG. This would work particularly well with ACKS domain rules (and an aristocrat class!), and reminds me of the Punnett Square, which I was thinking of.

You’ll need two genetically compatible parents, and one d4 (or in this case, a d20).

For each of the child’s attributes, roll your d20.

On a 1-5, the child receives the mother’s attribute value.

On a 6-10, the child receives the father’s attribute value.

On an 11-15, the child receives the average of the parents values.

On a 16-20, the child receives a randomly determined value, as in character creation.

I haven’t done the math, but at first glance it seems this method would produce royal families whose average attributes were noticeably skewed towards those of their progenitors.

The interplay between status and Charisma value would be interesting to model here, because assuming that both status (wealth) and Charisma contribute to attractiveness and genetic fitness, then those without wealth but with high Charisma would be more likely than those with low Charisma to breed with the wealthy, and so forth.

You could add social status to Charisma to get a new value (Aristo-fitness?), and when world-building, have the mates of a given aristocratic NPC have this same value.

A less charismatic mate would then be of higher status, indicating perhaps an “arranged” marriage of political convenience, while a more charismatic mate could be of lower status, having charmed their way up the ladder a bit.

(Depending on the relative values of “Charisma” versus “Social Status”, this could also model an aristocratic taboo against marrying too far beneath your rank, as even the most charming peasant couldn’t expect to marry an Emperor or Empress.)

Then once you have some kings and queens, you can generate their kids as above!

Huh… this looks like it will work more entertainingly than my plan of “1d6 + (mother’s score + father’s score) over 3 round nearest”. I agree though, that multi-generational play is a really neat idea. Hopefully eventually I’ll run a campaign long enough to see it happen :\

Very nice idea!

This is an interesting method!

I’ve been planning something similar for my campaign, but since the PCs are still a long ways from that, I haven’t yet decided on the exact mechanics.

One thing I’d thought about was this: roll 3d6 in order, but add the modifier of the parent’s ability scores (min is still 3 and max is still 18).

So if Chlodomer married a CHA +3 princess or something, their children would roll 3d6+6 for CHA. There would be a 25% chance of an 18, and no chance at all of less than a 9. However, even if he married an average-looking peasant, his own good genes would help drag the average up a bit.

The d20 roll above is another mechanic I might use, now.

When it gets closer to being needed, I will probably crunch out some example characters and see what each one looks like.

Very neat stuff.

In both methods, the average across thousands of parents and children will rapidly approach the average results of the original method used to generate ability scores.

For PCs, however, there will be a eugenic effect: because they will tend to pick (and be successful at picking) the best option for a mate, the ability score averages will drive upwards. How far upwards is largely an issue of GM and player interaction; PCs will encounter enough NPCs with a wide enough variety that the more cherry-picking they are allowed to do, the more powerful the eugenic effect will be.

The differences between the two methods amounts to this:

  1. The d20 method ensures that there 1–2 ability scores will be more random, but for the other ability scores, will tend to favor the highest results. In other words, each generation will have to suck it up on one or two scores, but the other scores will be cherry.

  2. The modifier-to-rolls method will tend to reduce how low the score can go, but 18s will tend to not pass on as often. In other words, the average eugenic effect will be about the same as the first method, but there will be fewer extreme results.

If you want reasonably predictable eugenics, go with #2; if you want wilder results, go with #1.

Did some further thinking on this, because I’m totally going to steal it :-).

The analysis I did above assumed that the children would use the exact same method as the parents for generating ability scores.

The example below rolled the original characters with the King method, and the children with 3d6, on the premise that the original characters were randomly selected for heroism, but the children are what they are. In both cases, the average was dragged down somewhat, but the effect was more pronounced in the d20 method (which can more aggressively cull the highest stats, even if it doesn’t do it often).

Ali [16,  9, 16, 12,  6, 16; avg 12.5] and Ama [11, 10, 17, 17, 15, 17; 14.5] meet, charm, and marry one another, and then manage a terrifying number of children:

Using d20 method:
[11, 10,  8, 17, 10, 16; avg 12]
[16, 15, 17, 17, 10, 17; avg 15.33]
[10,  9, 16, 12,  6, 16; avg 11.5]
[16,  9, 16, 12,  6, 17; avg 12.66]
[ 8,  9, 17, 10, 15, 16; avg 12.5]
[13, 10, 16, 12, 15, 10; avg 12.66]
[11,  8,  9, 17, 10, 16; avg 11.83]
[11,  9,  9, 12,  6, 16; avg 10.5]
[13, 10, 16, 14, 10, 16; avg 13.16]
[16,  9,  4, 14,  6, 16; avg 10.83]

Overall average 12.3

Using modifier method:
[18,  8, 17, 14, 11, 14; avg 13.66]
[13, 11, 15, 18,  4, 11; avg 12]
[ 9,  5, 13, 15, 11, 16; avg 11.5]
[18, 13, 17, 14, 11, 14; avg 14.5]
[11,  6, 18, 14, 12, 12; avg 12.16]
[13, 17, 18,  7, 13, 18; avg 14.33]
[ 8, 12, 18, 15,  8, 15; avg 12.66]
[10, 17, 15, 18, 11, 17; avg 14.66]
[14,  5, 18, 16,  9, 17; avg 13.16]
[11,  9, 14, 16, 11, 15; avg 12.66]

Overall average 13.1

A few additional comments:

The d20 method results in a lot of clone-ish kids. Ali and Ama only have one standout high-DEX kid, and one standout mediocre-CHA kid. Everything is kind of same-y, even with the duelling CON and WIS.

The modifier method results in a lot of really high scores. Even with a reasonable average result, there are way too many 17s and 18s running around.

I think if I was going to do this, I would roll 1d6:

1: inherit from parent A + 1d3-2
2: inherit from parent B + 1d3-2
3-5: inherit average of A and B + 1d3-2
6: roll 3d6; if both parents have a positive modifier, +1; if both are negative, -1.

Mind you, this method is more complicated. The only reason I would do it is because I have a computer and I am a programmer, and I would never be making all of those rolls myself.

Here are Ali and Ama’s kids with that method:
[14, 11, 15, 11, 15, 17, 13.83]
[14,  8, 16, 14,  9,  7, 11.33]
[14,  8,  9, 14,  7, 15, 11.16]
[14,  8, 17, 13, 11, 11, 12.33]
[11,  9, 18, 13,  9, 15, 12.5]
[12,  9, 15, 11, 15, 16, 13]
[12,  8, 17,  9, 10, 16, 12]
[ 6, 10, 17, 13,  9, 16, 11.83]
[ 9,  8, 17, 10, 11, 14, 11.5]
[17, 10, 15, 13,  9, 16, 13.33]

Overall average 12.3

Still looks a bit clone-ish on DEX, but not quite as bad everywhere else.


1d3-2 seems like a great way to introduce just a bit of additional variation, and I like the spread from your method the best of all three.

I’d love to see this turned into an ACKS Tool!

One could also include a way of having the parents’ classes and proficiencies influence the proficiencies of their 0th-level children, as well as the classes and templates of their more adventurous 1st-level offspring.

Assuming some kind of hereditary succession, this would make domain-level play that much more interesting. :slight_smile:

Just wanted to add, the last revision’s spread of scores looks the best to me, too.

And is it sad that I want an ACKS Tool for everything now?

Another option would require the GM to start the game with the intention of using dynasties. Record the actual dice rolled for each stat (so, if the 3d6 for a stat were 2, 3, 5, then those values would be recorded in addition to the total of 10). When a child is born, roll 3d8 for each stat. On a 1-6, use the value rolled. On a 7, use the die result for the father. On an 8, use the mother’s die value. You’d have to record each die as 1st, 2nd, 3rd, and decide on 1st, 2nd, and 3rd for each of the d8. That allows the parents to have an influence on their children, but doesn’t make every child born of the parents the same. Alternately, if you want more influence from the parents, use 3d10, with 7-8 being the father’s die, 9-10 using the mother’s, or 3d12, with 7-9 father, 10-12 mother.