This came up in yesterday's game - we were discussing how to accommodate a farie lord who wants to make "Improvements" to our covenant, and who doesn't like the aura effect of the Aegis. One suggestion was to give him a casting token. His response was that he would have much too many assistants than we had tokens, and therefore would require that we not have an aegis for a year. The counter-offer was that we put a suppression effect on the Aegis, so that when his workers were there we could suppress the Aegis, and then pop it up when they left. (And we would have more standard ring-based effects up during that time as partial defense.)
However, one of the players commented that because the Aegis isn't fully incorporated into Hermetic Theory, you couldn't just "turn it off" like you would any other hermetic effect. Another point brought up was that Vim magic usually required that the ReVi effect would have to be a Ritual effect, because an Aegis is a ritual.
Are either of those the case in the RAW? My own personal thoughts are as follows:
- Regardless of whether or not Aegis has been incorporated fully into Hermetic Theory doesn't mean it can't be affected by other Vim effects. (Perdo Vim explicitly allows a mage to cancel out non-hermetic magic, for example.) Rego Vim also discusses "any magic" as part of the general guidelines. That being said, there may be a case for Muto vim effects not working, as they require Hermetic magics to be the target. And it could be argued that something that is not full incorporated into Hermetic Magic isn't, technically, Hermetic Magic.
2a. The rule about having to use rituals to affect rituals feels...correct, but I can't find the guideline for that. Does anyone know a specific page number? I can glance through the Perdo Vim effects and see that you need a ritual to Disenchant an item, but that's it. I could have sworn there was something specific, but I can't seem to find it. (Not seeing it in the general Vim description, for example.)
2b. That being said - for a Rego effect, even if it wasn't the case you'd functionally need a ritual for all but the most basic Aegis-suppression, as it requires a doubling effect in order to work.