Here are some thoughts on meta-traits, for those relatively new to GURPS and wondering how to use them effectively. Some of the advice might help more experienced GMs as well, if only by reminding them of the reasons meta-traits make life easier overall.
Meta-Traits (p. B262) are package traits. They collect a set of advantages and disadvantages into a short name you can apply to creatures and characters. This post assumes you've read the description and examples on p. B262-3.
Why use them?
There are a few reasons I like to use meta-traits.
- They ensure everything of a like kind gets all of the same effects. If every demon in your world is Immune to Metabolic Hazards and has Doesn't Breathe and has Dread (Holy Objects), it's just easier to put them in a meta-trait called Demon and stick that on every demon than to remember to put each of those on each demon you generate.
- It vastly speeds up monster generation if you don't have to comb through all of the advantages and disadvantages to find what you need each time. You never get caught out thinking, "why doesn't this wild animal have Bestial?" because you just bolted on the Wild Animal Trait which includes it.
- It makes modifying creatures a much simpler task. The idea is to speed up and simplify the process of making and playing a creature.
For these reasons, I use meta-traits aggressively in my creature descriptions for my games.
What are the downsides?
Nothing is free of downsides.
- You have to know the package. If you're wondering if skeletons have Immunity to Mind Control because you didn't check if it's in the Mindless Undead meta-trait, you'll know what I mean. Any meta-traits you use, you need to keep track of. Know them before you use them. Know that Body of Fire means "know the stuff on B262 is on there."
- They come with everything on the meta-trait. Obvious, I know, but the point is that by choosing the meta-trait you're accepting all the items on the list pending subtractions. The bigger the trait is, the less broadly it is able to be used.
Some pro tips:
- Make it the minimum overlapping set. It's easier to add more traits (and more meta-traits) than to keep track of subtractions. If the creatures with the exceptions are truly rare, or the subtractions are single traits with no spillover into other traits (for example, SM modifying cost), it'll be okay. But it's generally easier to add more traits or a new meta-trait than to say "This without that." The moment you end up with, say, Dwarf (Remove Greedy, Add Miserliness and Callous, Remove Lifting ST) you end up with so many changes to track it would be easier to just list the parts that are there.
- Don't be afraid to use multiple meta-traits. A demon-dog might have Wild Animal and Demon. An air elemental-like mindless slave might have Automaton and Body of Air. And so on.
- Stay on topic. If you mix too much into a meta-trait, it becomes less broadly useful. "Rubber-Bodied Alien" is not as good as "Alien" and "Body of Rubber" because you can't use the former easily for non-aliens or non-rubber bodied types, but the latter are useful on their own.
- Make the meta-traits as simple as possible - don't include a lot of if:then or "raise X by Y" in them. The DF prefixes do this, it's true, but they also require a little more work to use. Once you start including variable modifications, expect the work load for using the meta-trait to go up.
- Use meta-traits to drive campaign themes. If all of your demons are unable to harm the truly innocent (directly), or all of your golems can only be disabled by removing their scroll, or all of your bug-eyed aliens have Lecherousness (after all, Mars needs women), put that kind of stuff in a meta-trait and use it widely. This will ensure players begin to see the patterns in creatures, and understand what drives them or harms them. It helps to establish a shared experience because of the commonalities between creatures.
Compare that to making up each demon, golem, or BEA separately. If each is basically different, with no common trait beyond a name with no shared game effect, then it's just a name. There isn't a predictive knowledge to be gained, just a pool of possible effects ("Demons can't harm the truly innocent. Well, some of them.")