A question that came up while designing an NPC for our troupe. The NPC in question (a Tytalus) wants to control people's minds with her talisman. Naturally a crown seems suited to this purpose as it grants a bonus in the shape and materials table. But, being a paranoid Tytalus, she does not want to walk around wearing a crown and announcing her intention to control every mind that she comes across. A possible solution is an always on Muto Terram effect that turns her crown into a much less obtrusive necklace. We are split on if this works:
The "this works" camp argues that the crown's essential nature has not changed. So the crown's bonus still applies, even if it looks like something else entirely.
The "this does not work" camp argues that the shape and materials table does not offer an essential nature bonus, it offers a shape bonus. The shape of the object has changed, so the bonus does not apply.
I'd be interested to know if either of these arrangements are persuasive, or if there is something else entirely we have not thought of!
If I was a Bjornear Magus, or a different shapeshifter magus, and had a talisman, and it didn't work hen shapeshifted I would be frustrated. SO I think it did not change its essential nature. However, is I was SG I would put a note to return to this... for example: next time that Tytalus magus has a Twlight Episode or gets a Twilight Scar, I would have the nature of the crown show through... maybe he always has the faint golden glow of a crown over his head, no matter what happens.
With that said, it does not need to be a large crown to be an effective talisman. A small crown on a necklace would also work!
I would go with essential nature. Perhaps the biggest reason would be because otherwise you could reshape something repeatedly to get all sorts of other bonuses out of it. For example, I want to enchant my dagger talisman with something protective, so I change it into a shield for the season to get +5. But now I want to enchant my dagger talisman with a touch effect, so I turn it into a glove for the next season. I really dislike where shape bonuses being tied to temporary shapes heads. The essential nature method avoids this problem. It also avoids the same problem with materials, since you can change not only something's shape but also its material. It seems to me like bonuses being tied to temporary shapes and materials would do away with the need for finding certain special materials in the first place, which would make talismans less special and unique.
I really can't see using shape bonuses for items currently lacking the desired shape. It's really stretching it to argue that a lump of gold in the shape of a crown has an essential nature of "crown", particularly since it can be changed into, say, "ball" with nothing more than a hammer.
I could go either way on material bonuses, I suppose, but I'd be inclined to change them also, as Muto is specifically real, albeit temporary.
I can't see that coming up in practice. Your magus is casting a ritual - season length duration - Muto just to get a few points bonus on an enchanting lab total?
Why a ritual? My magi cast season-long non-ritual spells, including spontaneous ones, all the time. It's fairly trivial, though in this case you'd want to be decent at Muto.
Huh? No, nothing exotic. You just cast D: Concentration and use a D: Moon version of Maintaining the Demanding Spell. Renew that maintenance spell as needed. Your spells can theoretically last forever.
You can avoid ReVi if you want, and just use overlapping D: Moon spells. The special thing with D: Moon is that overlap period that is so different from D: Sun.
One of the magi in my saga wanted a crown with lots of different gems in, but didn't want to look ostentatious - so he made his crown invisible. He was fine most of the time, but the inevitable shepherd with second sight occasionally made things awkward.
That flicker should have bad effects on an ongoing enchantment.
Similarly, this isn't really one spell but a sequence of spells starting and expiring. I don't normally like to be hard on players but in this case they're the ones trying to munchkin out, so I'd definitely apply enough safety penalties in the lab to make it not worthwhile.
Maintaining the Demanding Spell, regardless of duration, is pretty clearly the same effect as the device maintains concentration enchantment effect modification and should flicker in the same way.
We are talking about items opened for enchantment, are we not?
If you spend a season infusing Vis into a lump of gold during the opening for enchantment, I would lean towards the idea that you are "fixing" the essential shape (in terms of further enchanting bonuses) of the lump of gold as whatever shape it was during the entire season. If the lump of gold was shaped as a crown, then it will have the essential nature of "crown" in future enchantments.
I am sort of extrapolating from the ability to fix an arcane connection to be permanent.
You are using some distinctly non-canonical interpretations here. I'll go through the duration issues:
First, Sun is the only duration affected by sunrise/sunset. This doesn't apply to Concentration, Diameter, and Moon, for example. See ArM5 p.112. I don't know why you're forcing sunrise/sunset on non-Sun spells.
Second, items maintaining concentration lose their concentration at sunrise/sunset, though their effects may not be (such as Moon-duration effects). This applies explicitly to items, but nowhere is there any comment about it applying to people concentrating. Not only that, the book makes it clear people can concentrate on such effects right through sunrise/sunset even when an item cannot...
Third, the core book is clear that you can "perpetuate" a Concentration effect in an item through sunrise/sunset even though a device loses its concentration at sunrise/sunset by concentrating on it yourself. See p.99 and Speech on p.105. If you forget, the item will drop the spell, but if you remember, the spell stays active and needs no more uses to keep going. As long as you're doing the concentration through sunrise/sunset, the spell may be perpetuated.
Fourth, since you can maintain a Concentration spell yourself through sunrise/sunset, even a regular Maintaining the Demanding Spell can make a spell last forever. The problem is that you'll have to keep replacing it roughly every diameter. That doesn't give much time for sleep or anything else. Sun works, though you have to take over twice a day. Moon works far better...
Fifth, in the case of Moon, you don't even need to take over. While you're treating it like Sun, Moon functions very differently. I'll show you. You cast your spell and cast the Moon-version of Maintaining the Demanding Spell. The new/full moon arrives. The spell continues. You cast another maintenance spell. The next new/full moon arrives. The first maintenance spell fails, but the second one keeps it going for another two weeks. You cast a new maintenance spell. This is very different than D: Sun because you have overlap instead of a gap between the durations. Diameter can be used the same way; it's just more of a pain, as mentioned above.
I was trying to figure out what exactly bothered me about this argument. Now I see. Why does it matter if it's the same effect or not. We're looking at the case where things like essential nature don't matter. So who cares? Since all that matters is the shape at the moment, just keep the shape at the moment going and you have the same shape the whole season. Moon provides overlap, so there is no loss of the shape. Or are we starting to say that essential nature really should matter?
This is what I was referencing. Nothing to do with Sun or Moon.
I read the text of Maintaining the Demanding Spell to be exactly the same as the enchantment enhancement. The spell or item maintains concentration for the caster. It could be that one flickers and the other doesn't but it's always seemed more consistent to me to have them behave the same.
For a crown that's just sitting on someone's head or a dagger that's just being used to cut, it shouldn't matter at all. An item under the subtle mix of magics used in an lab to produce an enchantment effect is something more sensitive. I'd rule that the interplay of spells interferes. As I said, this is being picky and players may object by imo they've got it coming if they're trying to abuse the system with "This is a Crown but right now it's a dagger so I can get a +2 bonus this season!".
But it's not at all nothing to do with Sun/Moon. The spell explicitly references its own duration, which has absolutely everything to do with Sun/Moon here. Meanwhile, an item maintaining concentration operates on the same sunrise/sunset that applies to Sun duration and not to Diameter or Moon. Read them again, and you should note that there is one very specific difference in the descriptions you claim are the same: an item maintaining concentration "start[s] to wear off at sunset and sunrise" while Maintaining the Demanding Spell says "for the duration of this spell." In the specific case where you make the spell with the duration Sun, then that duration is "until the sun next rises or sets," which now matches. But if the duration of this spell is Moon, then it's "until both the new and full moon have set." So my big question is, why are you saying a Moon-duration effect would not be a Moon-duration effect? I really cannot fathom it.
Second, you're still not showing any flicker anyway for all the other cases. Where is the flicker when a person maintains the concentration from a enough before sunrise/sunset (before it starts to wear off) and right through sunrise/sunset with the item. Then it's operating under the person's concentration regardless of what the item does. We can see that "The spell lasts as long as the magus concentrates. In the absence of distractions, assume that a magus can concentrate for fifteen minutes per point of Concentration ability. If there are distractions, see the rules in the Hermetic Magic chapter, page 82," says absolutely nothing about sunrise/sunset playing into it. Not only that, the comments about items concentrating show specifically that a person can maintain concentration through sunrise/sunset even if the item cannot. So, why must there be a flicker? Sure, you could wait until the last moment so that the effect has started to wear off, you need not wait that long. Why, if the effect hasn't started to wear off at all when you take over, must there be flicker?
Maybe I'm not being clear enough in why I suggest flicker.
I see Maintaining the Demanding Spell, AM5 pg.162
as being the same effect as the Concentration effect modifier for enchanted devices, AM5 pg. 99
Arguably, this may not be the case but the language is strikingly similar and it makes sense to me at least to treat the two as analogous. I believe this to be the case regardless of whether the Maintaining the Demanding Spell is cast at the listed Diam duration, or reinvented with Sun, Moon, or even Year. Of course, the situation won't arise using the Diam version printed in the book.
If so, you're still not being. Look more closely at what I'm saying. The magus, not the Sun-duration spell or the item, concentrates on the effect from before the item/spell starts to fade. The magus continues to concentrate on the effect until well after sunrise/sunset. The magus then turns the effect back over to the item/spell (new casting of the spell). So the item/spell is not maintaining the effect anywhere near when the item/spell is fading. Therefore, the maintaining item/spell has no relevance at all. Why are you saying Concentration-duration spells being maintained by a magus concentrating must flicker? I can't find anything supporting that in the rules, only things suggesting the opposite.
Meanwhile, I'm still wondering why you're saying Moon-duration effects fade at sunrise/sunset.