Assuming a Merinita maga with a faerie knight (e.g. Sir Excelsis, RoP:F p.84) as a familiar, what would you allow the shared power (as per HoH:MC, p.89) of "Shift Human Shapes" to do for the maga?
Not a thing?
And why not?
Since the armor is prolly glamour, it would protect the maga just as badly as it does the faerie. Remember that faerie's wound are also glamour and won't affect the knight unless required by the story. Your maga's wound are real.
The power's description (RoP:F, p.62) doesn't mention anything about glamor though and isn't specific to armor either.
Actually the faerie knight's armor provides him with the full +9 soak bonus.
Well, the last sentence is "As an example, some faerie knights use this power to don armor by transforming the outer layers of their bodies into layers of metal."
p10: "The clothes and tools of faeries are usually parts of their bodies, created by their glamour."
p47: "A faerie does not suffer Encumbrance for pieces of equipment traditional for the role it is playing, because these props are made of glamour."
Yes, mecanically it does. In the same way a turtle shell would since it's part of its body/glamour.
Remember that you asked what we would allow. Since the maga has no glamour she cannot change the shape of her body that way. That would be my starting point for negociations.
... which makes it a MuCo(Te) effect, which is equally applicable to (human) magi.
This doesn't relate to "Shift Human Shapes" at all. His horse is part of his glamor. His sword is part of his glamor. Both are not a power - so "having them" is not something that is shared. "Shift Human Shapes" on the other hand is a power and - in its basic description - not specific to glamor.
Again: I'm not talking about having a chainmail or a turtle shell (the latter also wouldn't be a power into itself), but specifically about "Shift Human Shapes" a.) in general, as per its basic description, and b.) in this specific case - would you allow the more general application as per the description or just the very specific effect?
I'm also interested in the reasoning for points I might disagree on. You don't need to be composed out of glamor for a Muto Corpus effect to take hold. I can see how you would argue that you can't affect regular armor if you only grant the shared power in its most specific incarnation, unless this armor was created by a MuCo(Te) effect from the maga herself. (It's weird that the power's description mentions the Terram requisite for this specific use of the power, but the Faerie Knights themselves don't apply it in their version of the power.)
Yes, you can have an hermetic equivalent to the power. It doesn't mean the power is hermetic.
A faerie's body is glamour. The armour is also glamour because it is the transformed "outer layers of their bodies".
Now, maybe we should look at the other faerie powers and try to deduce a pattern. How many powers would require some glamour on the maga?
Also, "Any opening of the body allows faeries to attempt to influence the character of a human." (p 11), which could be construed as the maga being immersed in the glamour of its familiar.