So we all know that the debate rages hot on the specifics of botching, mastery and rituals.
But lets assume, for whatever reason, that the Aegis ritual is botched. What are some possible outcomes?
Here's a few ideas for starters:
The entire / part of the covenant gets thrust into a regio.
The entire / part of the covenant gets ejected from a regio.
The Aegis affects only people who participated in the ritual.
The Aegis affects absolutely everyone.
The Aegis wards against anyone without magic resistance or a might score.
The Aegis' penalties become bonuses.
The Aegis amplifies the social effect of the Gift for all participants.
Time stops within the Aegis, and resumes when the spell duration ends or later. The inhabitants/participants are none the wiser.
Everything and everyone inside the Aegis gets warped as if they were in a strong aura.
The Aegis looks fine, but comes down at some point during the year (either on its own or when it would have blocked something).
It destabilizes the aura until it ends, causing any spell cast within to additional botch dice, for example as if it was a Faerie aura (appropriate if one of the participating magi is a Merinita).
The Aegis is visible, so that any mundane immediately notice it as a supernatural phenomenon, with perhaps some secondary effect related to the sigil of the caster. For example, a Flambeau might have caused the Aegis to manifest as a dome of crackling flames visible for miles (particularly at night), so that anyone entering or exiting it must protect himself or suffer superficial burns, while local authorities might consider it a sign of diabolical activities.
The Aegis as a side effect on anything and/or anyone inside, again perhaps based on the sigil of the caster. Such as making them blue, or blind, or invisible. Or perhaps all food tastes like ashes, or spoils within a day.
The casting of the Aegis attracts some supernatural creature(s) so that it (they) begin plaguing the covenant. Not necessarily because it wants to attack; it could be that fauns keep partying all around the Aegis for a year, driving people inside nuts from their music and carousing (and keeping the grogs mostly drunk for a year).
Etcetera, etcetera, etcetera. Adjust the severity based on the number of botches.
The worst problem is that it probably goes against the game contract established by determining the Boons and Hooks of the covenant. I'm all for changing the narrative of the [strike]game[/strike] story for certain die rolls, but this changes the narrative of the saga for every single player, for at least a year.. Grogs have to fight more monsters, which they never had to before, or as Arthur suggested, it attracts unwanted attention where the fae play music all night long. Magi have to get roused from their routines to deal with this. In a story, if a single roll goes bad, it might involve the death of a character or a Twilight episode and many deaths, but it is isolated to that story. A botched Aegis alters everything for the entire covenant at their home base.
Roll on the experimentation chart, see what happens on that. An aegis with a magnified sigil, for example, isn't bad, just... irritating, depending who's sigil is the prime manifestation (and if using wizards communion, do you manifest everyone else's sigils slightly too? )
Sure. It doesn't do anything about the botched Aegis, though. At best you have a properly functioning Aegis on top of what other detrimental effect that is the botch. But, and this is a big one, how do magi know if there was a botch, unless they had a double botch. A Single botch might not have noticeable effects and afaik you can't tell when your warping score increases. So, only a double botch gives enough of a sign, due to the Twilight avoidance/episode.
I tend to run Ars Magica so that non-grog characters only die when their players want them to. That doesn't mean that I think that should be written into the game's rules. (Although it was, in an early draft, which is why the "dead" wound level does not appear with complete consistency in character descriptions.)
Similarly, if you think that botched Aegises will break your saga, house rule them to not botch in whatever way seems appropriate, or always choose botch consequences that do not break your saga.
Incidentally, my reading of RAW is that Mastered Ritual spells have no botch dice when cast under calm conditions, because the description under Ritual spells says "always use a stress die", not "always count as stressful". I suspect that that was my intention at the time, because a number of ArM4 to ArM5 changes in that section were designed to create a background where magi could use magic to do casual, everyday stuff without statistically exploding with unnerving frequency, but it was over ten years ago and I don't remember exactly what I was thinking at that point.
David, thanks for the clarification. The implication is that everyone will master a ritual in exchange for a season and all castings will, unless the SG makes it stressful, be without risk. So, there is a huge varianc between safe situations and stressful situations that suddenly come into play.
Your covenant aegis has just come down as a result of hostile action from a rival covenant. Their army of dark faerie allies will be at your gates by nightfall. If the Aegis is not up, all your grogs will die.