I'm planning a custom power to honor the psionic deity Auppenser and his desire to separate psionics and magic. I was planning on having a power that allows you to manifest other powers you know as versions of themselves that ignore psionics-magic transparency. I was wondering what the ramifications of having no Psionics-Magic Transparency are?
This is not as hard as it may seem at first
I play almost exclusively psionics (99+% of the time), so I have some background to make a few comments.
If psionic-magic transparency is removed (most commonly done in campaigns involving some sort of invasion and/or crossing over of "planar-aliens" from an alternate Prime) the simple result is that nothing magic can defend or prevent anything psionic from affecting the target. Likewise, nothing psionic can defend or prevent anything magic from affecting the target.
My gaming experience has proven to me that this is actually trivial to adjudicate on the fly. Practically no preparation is needed other than a change in mindset. Your individual mileage may vary. Please see my note at the bottom for more on this.
Now, having said that, there are some difficult points to consider, some of which I will illustrate:
- Direct versus Indirect. The first point of contention that will come up is whether effects produced by magic are magic in and of themselves? If they are, then psionics can't defend against it. If they are not, they it can. This is where another answer mentioned going through every effect in the game in advance and referenced ad-hoc rulings. (Which is still not difficult to do, if one takes notes of rulings as one goes.) For this question, it is simplest to rule that primary effects are still magical, regardless of what damage type they do, or what visual and other sensory effects they produce. However, some DM's like the idea of magical fire being able to counter a psionic cold attack, so adjust it to your table's preferences. Be warned that if you do so, however, you WILL wind up having to ad-hoc a greater amount of stuff, as another answer has pointed out.
- Direct versus Indirect - part 2. What about secondary effects? That previously mentioned fireball was very likely to set normal combustibles on fire, and if it did, are these fires magical? It is simplest to rule that any secondary effects (ie: effects that are not specified in the spell itself, such as stuff that is still burning after the spell is gone or spells that leave water or sand on the ground after the spell effects expire, etc.) are not magical, which would allow psionics to defend against it.
- Direct versus Indirect - part 3. What about armor and weapons? Well, both psionics and magic provide the same bonus type for AC and to-hit, so it is simplest to allow these to still be effective against either (see also point 4). However, a strict interpretation of non-transparency would imply that magically enchanted armor is nothing but bare metal against a psionic effect, and that fine psionically enhanced crystal armor is but a fragile chunk of rock when opposing magic. Note that other magical or psionic effects would be ineffective against each other, however. Flaming swords will ignore fire defenses and life draining will ignore protections against negative energy, if they are crossing the psionic-magic divide.
- Direct versus Indirect - part 4. Math. If the strict version of non-transparency is used, then you have to recalculate your AC and to-hit separately when crossing the psionic-magic divide. Rather a pain, this. And another reason to simply permit weapons and armor AC and to-hit bonuses.
- Away-ground advantage. The away-team (usually psionics, unless you are in one of my campaigns), will have a serious advantage against the home-ground (magical) defenders. Why you ask? Well, in a high-magic world, magic items are common and easy to obtain, and are likewise easy to use. Most of them you just put them on, or say a key word. Psionic invaders could easily pick up some stuff and use it, gaining magical defenses, while retaining their non-transparent psionic advantage. I consider this sort of thing to be a grand challenge, but most people will whine about brokenness, unbalanced, and unfair. My response to that? Ever tried life lately? Anyway...
- Away-ground advantage - part 2. Unlike psionic invaders, magical invaders would not enjoy the same advantage in psionic items. Why? Many psionic items have a "mental addressing" scheme to activate them, which some DMs may rule that magical-based characters, lacking the "psionic creature" designation, therefor cannot activate a mental-based item. Which would mean that they can't figure out how to use said items without a UPD check. Which they don't have skill ranks in. Others may take the Magic Item Compendium as the basis, and rule that as the psionic items listed there communicate mentally with their owner regardless of owner ability. The former is more "strict non-transparency" than the latter. Also keep in mind that there ARE spells which allow mental communication. Having to re-cast one every time one wants to activate certain items is still a significant disadvantage, however, which therefore should be considered seriously before implementing.
- UPD versus UMD. One can always finagle a way to purchase cross-class ranks, or figure out how to qualify for the skill, once any DM requirements have been met.
- Summons Summoned creatures (astral constructs or summon monster effects) could be considered to be psionic/magic in and of themselves during the effect duration, and some DMs may wish to treat it as such, though it is simplest to treat the summon part as the psionic/magical part, and the creature as whatever it is. Note that creature abilities may be considered psionic/magic, which again, could not be defended against by the opposite.
- I have not covered everything, just a few salient points. So, please consider carefully before making such a spell (or using non-transparency, for that matter.) If one is prepared, it will work out well, if not, you run the risk of the campaign not going as hoped or planned.
Please note, I'm a psionics nut, and have been ever since they released rules for player psionics in D&D. As such, I have a very slanted view towards psionics, but also have a lot of gaming experience to back it up. On the other hand, I'm not nearly as familiar with the magic system, (and I can't stand Vancian-based magic systems in general, anyway) except as for how to defend against it using psionics. ^^
It's probably easy for me to adjudicate transparency issues on the fly due to familiarity and lots and lots of practice. Again, your mileage may vary, and my comments are not to be taken as a slam on anyone, as that is not what I intend. (But feel free to take it as a slam on the magic system! cough Not that the psionics system is any less "breakable", to be fair. cough)
Reference material: The Multiverse Wars trilogy
You have to go through every magic effect in the game that interacts with spells, and decide whether it interacts with psionics or not, and if so, how so.
You have to go through every psionic effect in the game that interacts with powers, and decide whether it interacts with magic or not, and if so, how so.
You have to go through every feature of every race, class, and creature in the game that interacts with magic, and decide whether it interacts with psionics or not, and if so, how so.
You have to go through every feature of every race, class, and creature in the game that interacts with psionics, and decide whether it interacts with magic or not, and if so, how so.
And you have to do this. You cannot skip it. You cannot make ad hoc rulings on the fly as they come up. If you skip it, try ad hoc rulings as you go, you will wind up with a game where one or the other is broken, able to ignore too many things intended defenses. The balance of the game, weak to begin with, will become unmanageable.
Psionics was never designed to be different. They should never have suggested it could be. You would more easily write your own system than you would make psionics actually work differently in 3.5e.