I had originally planned to write about how autoscaling magic items are enchanted (“construction of an autoscaling magic item”) but it makes more sense to describe what they look like mechanically first.
First, consumable magic items really aren’t appropriate as autoscaling items. The whole point is that the items will grow with the wielder, and something that can be easily used up just doesn’t make sense. Items that are ‘partially consumable’ (such as a luck blade) can be viable autoscaling items because they have additional features that are permanent. “Autoscaling staves” will need to be a bit different from standard magic staves.
Second, autoscaling items by definition need to be able to become more powerful at higher levels. The Big Six are definitely candidates, other items might be appropriate.
Third, an autoscaling item will have a base effect. This base effect will likely not have any unusual requirements such as the scaling components will.
Fourth, an autoscaling item may be fully- or partially-defined. If fully-defined the items powers and effects are all known, and the wielder need only meet the requirements to gain the effect. If partially-defined then powers and effects are known only to a certain point (and the wielder need only meet the requirements to gain the effects), but the wielder has the option of extending the scaling effects.
Each autoscaling item has two ‘tracks’ of effect. One is drawn from the Big Six (enhancement bonus to attack, enhancement bonus to armor, natural armor bonus, deflection bonus to armor, resistance bonus to saves, and enhancement bonus to ability scores), the other is usually a more qualitative effect.
An autoscaling item has ten ‘slots’ for effects, each associated with two character levels (first slot is associated with levels 1 and 2, second slot is associated with levels 3 and 4, and so on). Each slot will contain effects from the primary or secondary track, and will have requirements that must be met to gain access to the effect. Normally each track will have separate requirements, and it is possible to advance in only one track. Together the effects should be roughly appropriate for the level of the slot.
Example: Beobachten, the Dragon Watching
Enchanted arms and armor are the simplest to define here, since they can be expected (in the right hands) to scale from +1 to +10 effective enchantment. This aligns rather nicely with the ten slots of the autoscaling item and their associated levels.
I originally wrote about Beobachten, the Dragon Watching a few years ago, a dragon bound into sword form. For the sake of example I’ll rework it here to align with these rules.
|flaming spell bane
|Appraise 7 ranks, Use Magic Device 7 ranks
|flaming spell bane spellreaving
|Appraise 11 ranks, Use Magic Device 11 ranks
|flaming burst spell bane spellreaving
|Appraise 15 ranks, Use Magic Device 15 ranks
|seething flaming burst spell bane spellreaving
|Appraise 19 ranks, Use Magic Device 19 ranks
The seething weapon property is a +2 property that does +2d6 points of energy damage (in this case fire) instead of +1d6, and overlaps the effect.
The spell bane weapon property is a +1 property that acts as a normal bane weapon (additional +2 to hit and +2d6 damage) against foes that cast spells or use spell-like abilities.
The spellreaving weapon property is a +1 property forces casters and creatures using spell-like abilities to make a caster level check (DC 11 + wielder’s level) or lose a highest-level spell slot or spell-like ability daily use as if expended.
Beobachten was originally a red dragon and was bound in sword form by a wizard. He still holds a grudge (as indicated by the spell bane and spellreaving weapon properties).
The base effect is as a +2 spell bane bastard sword. This sword might be most effective in the hands of a wielder that will satisfy its lust for treasure (represented by the Appraise skill requirement) and use magic (Use Magic Device requirement) while not necessarily being a caster.
Not the best example, perhaps, because Beobachten holds such a firm place in my mind with the current implementation.
It is evident to me that as written this will need either a more organic method of increasing certain effects (i.e. staging from +1 equivalent to a higher equivalent) or outright replacement as ‘more resources come available’. It may be that higher-grade effects will simply have to wait until higher level to come available, leaving empty slots in the table (which I don’t like).
Hrm. Not quite where I want to be with this.