I am currently trying to create a covenant full of NPCs where my troupe will go sooner or later.
That covenant is located in an old Roman site with powerful magical aura. It was a temple of Demeter, goddess of agriculture. Centuries ago a small regio appeared on that site and it now have two regio levels.
-The mundane site is a mundane swamp. The temple was destroyed by brutal barbarians around 650a.c.
-The first regio level is a small and humid valley with a few broken pillars and magical foxes of fire (though stupid ones).
-The second regio level has a Roman temple in the Center of a large area of blue wheat fields, looking like a sea of cereal. Here live the Floraliae, the local spring nymphs.
The Magi decided to live in the second regio level which provide a fine house and a comfortable aura.
If the Magi cast the Aegis spell in the first regio level, will it protect the deepest regio level (and the covenant) against visitors and the spring nymphs ?
Is it required to cast the Aegis around the second regio level’s entry to protect it ?
I think a lot of that has to do with how you perceive regios to function. If they are simply another dimension (in the classical definition) then the aegis should protect the same way it protects the air above the covenant- at least to some extent. However the fact is you can have regios which do not correspond exactly with the physical, suggesting that regios are more pocket universes which would not be enclosed in the spatial "bubble" of the aegis.
Then there is the fact that neither of these answers would make any sense at all to the 12th century way of understanding the world, which would probably perceive the regios as simply being "somewhere else, not of this world" which probably suggests that no, they would not be protected by an aegis at another level.
The thing I am wondering is if you have an aegis cast in a regio, and there is an entrance to that regio which enters within the aegis, can magical beings use that entrance without a token (or forcing their way in) or not? My assumption is not, but that also radically changes the idea of how an aegis and thereby a ward operate, leading to questions about summoning something within a ward...
I generally agree with this. I could see an argument for some regios that correspond to the physical world or each level strongly; This would be a trait of that specific regio rather than a fact of the aegis- the regio has the traits that they share 'boundary'. If the physical world is a hill, the first level is a ruined castle, and the second level is a glorious castle in full splendor, I could see the argument that level 1 and level 2 share the same boundary - that being the edge of the castle wall. If the level 1 is an empty field with a single tree, and level 2 is a full forest, I would argue they do not share a boundary unless something weird is going on.
I suspect that normally, they would be separate. But regio being what they are, there could easily be special cases. This situation doesn't seem like it ought to be exceptional.
It does mention in ROP:M the idea of an entire realm which is the metaphysical extention of a single object or person. If this applies to a regio and the object is inside the aegis then I could certainly see that working...
I think that it is wise to keep regios varied by keeping "it depends on the regio" as the answer for most general questions. My inclination is the same as Ovawara in that I think that the levels would require separate aegis' on most regios. That being said I like having regios being varied enough that having an aegis cover multiple or all levels isn't too weird.
This opinion springs from the discussions we've had about whether one can use an arcane connection to teleport or scry across regio levels, where either saying yes or no makes a lot of cool stories unworkable.