Some abilities and special items are defined in terms like “up to nine levels of spells, no more than one higher than fourth level and none higher than sixth” (house rules I’ve seen for magic staves) or “six benefits; you can triple one benefit and double another benefit, or double two benefits” (Masterworks from Green Ronin’s Black Company setting).
I like the idea of a benefit — item improvement, magical effect, or spells in an item — that aggregates fast but has a power cap lower than the aggregate. For instance, a magic item that allows “up to six spell levels” but limits the effects to no more than one third-level spell (you can’t include a spell higher than third, and if you include a third-level spell you can’t include two). I also like items that have a ‘major function’ and some ancillary ones to go with it.
The masterworks benefits follow a pretty simple pattern that I’d like to explore for other items.
A special item in this model — masterwork or spell trigger item, for example — has a grade. This will affect the price, provide an upper limit to the benefits that can be applied, and may influence other things such as the daily charges available for a spell trigger item. The grade also guides the highest-grade benefit that can be added at each step.
Every time a new quality is added to an item, the highest grade that may be added is equal to one-half the unassigned grade, rounded up. The grade of the quality is then subtracted from the item’s grade and another quality may be added. That is, a grade 7 item can have one power of grade 4, reducing the unassigned grade to 3. Another quality can be added but this one must be no higher than grade 2, which would reduce the unassigned grade to 1 (which obviously can only take a grade 1 quality). Alternatively, a grade 4 and three grade 1 qualities could be assigned, or a grade 3 quality, a grade 2 quality, and two grade 1 qualities (or a grade 3 and four grade 1 qua… you get the idea).
It is not necessary to assign all slots, but the highest grade will still be limited by the grade of the item. That is, you could create a grade 7 item with only a single grade 4 quality. The reason for this will become apparent in a post coming soon.
I’ve only shown up to grade 8, the number of permutations is making it silly to enumerate them. They could be abbreviated as “n*1 + f(grade-n)”, but that will take a bit of recursion to solve. That is, grade 8 with a grade 4 ability is “4*1 + f(4)”, which is either “2*1 + 1*2” or “1*4”. The key point is that it’s pretty flexible.
In the next post we’ll start to look at what can be done with this.