GURPS Power-Ups 1: Imbuements introduces a new system to turn your weapon into fire or make your weapon more capable of striking through armor. It’s been quite popular spawning multiple Pyramid articles (with at least two by Y.T.) and is used by many gamers. It’s a bit of a whole cloth system instead of one you can break down play with just the nuts and bolts. In my time as a game designer for GURPS I’ve picked up a few tips and tricks when designing new imbuements. This post is going to go into those a bit. I’m only looking at the imbuement skills from the basic supplement since that will limit the pool and give the best answers. We’ll look at the required Imbue level for skills, the schedule for penalties, and what the first level of each skill should cover.
First, there are 9 basic imbuements for Imbue 1, 12 for Imbue 2, and 21 for Imbue 3. You can design a new skill simply by using the rules for Temporary Enhancements (Powers, p. 172) and Abilities at Default (Powers, p. 173). The base value of the enhancement it adds to an attack determines it’s imbuement level, while higher penalties for the skill operate at -1 per +10% of the enhancement or 10% worth of the new ability its defaulting. (Note: I’m using the more streamlined version of Abilities at Default from GURPS Psionic Powers).
Example: Gina wants to make a new Imbuement skill that will allow her to “double” a weapon he already has so she can wield it dual handed or throw the double without losing the original.
Figuring the Required Imbue Level
All the lower tier skills are not flashy while still staying useful. For example, Ghostly Weapon is an excellent example of this. Being able to affect ghosts with your weapon isn’t useful until it’s useful. Imbuement skills requiring Imbue 1 tend to not have more modifiers to use them. Out of the 9 Imbue 1 skills five have no “higher level” modifiers to use and are just “as is.” Moreover, all Imbue 1 skills tend to add more control over the weapon in some way (e.g., Traumatic Blow) or transform it in a limited fashion (e.g., Deafening Display). Keeping with this Imbue 1 skills should at most turn a weapon into a secondary sense (such as Smell or Hearing), modify a single minor aspect of an attack (such as changing how a weapon delivers blunt trauma), or changing a weapon’s damage type into something on the lower-end of the scale (such as turning a weapon into a toxic or crushing attack). They tend not to have higher level modifiers and just “work.” When figuring the base cost of the modifier you’re adding or ability you’re defaulting anything +30% or lower is likely to be an Imbue 1 skill.
Imbue 2 skills use the same methodology, but are likely to have higher level or open-ended abilities that inflict penalties. When figuring the base cost of the modifier you’re adding or ability you’re defaulting anything +31% to +50% is likely to be an Imbue 2 skill. Imbue 3 skills are +51% or higher and often have very open-ended abilities that inflict large penalties.
When using Abilities at Default to change the nature of the attack, figure the cost of “basic damage” as worth 7 points (the average value of the 11 basic Innate Attacks per dice) when compared to other powers. For example, turning a weapon’s damage into Obscure Hearing is worth 28% of the value of the attack or about +30%.
Example: The GM decides that Gina’s “Duplicate Weapon” is closest to Melee Attack (Dual) (Powers, p. 103) making the base ability worth +10%.
Schedule for Penalties
Next, now that we’ve determined the Imbue level required we can determine the schedule for penalties for higher-skill uses. This is the easy part: simply add additional levels of the enhancement for imbue skills that add enhancements or add new enhancements to abilities that use Abilities at Default.
Example: Duplicate Weapon is effectively a lower tier version of Multi-Shot for weapons that can be thrown so the GM allows Melee Attack (Dual) to have additional levels. Having it duplicate an additional weapon per -1 to the beginning roll makes sense, so they add that as well.
Picking Over the Bones
This isn’t exactly a hard and fast system (as I’m sure you’ve noticed, dear reader), but guidelines. While GURPS has a reputation for being balanced and considered in its design so that you can pull apart the mechanical constructs to nuts and bolts to the very core. But not really. I mean, what is an HP worth really? Costs are arbitrarily arrived at in most cases when you get small enough. Everything else is built off that.
That’s how Imbuements work really. It assumes you’re adding enhancements or transforming an ability to something else from a base cost and goes on from there.