One of the difficulties of using everything is that it represents a large number of rule systems, including some that don’t mesh well together (for example, the finance rules in Covenants and the labour points in City and Guild). Many represent options sets that require decisions from each troupe before they are introduced, as they change the setting, the tone of the saga or the power level (such as Transforming Mythic Europe).
So I would propose a hierarchy of books, from the more vanilla to those only used for inspiration.
First category is what I consider “Core”. Pretty much everything described in them can be used without needing a whole lot of discussion, though there may be the occasional tidbit that need some tweaking or which may be set aside. It doesn’t mean that we have to use all of the content in there, but rather that these rules are available to anyone who would like to use them. Those would be:
- Ars Magica 5th Edition
- Houses of Hermes: True Lineages
- Houses of Hermes: Mystery Cults
- Houses of Hermes: Societates
- Covenants
Second category is what I consider optional add-ons. These are things we can pick and choose as needed or desired, but for which I suggest we obtain troupe approval on a case-by-case basis. Those would be:
- The Mysteries – except for the general mystery rules, which can be considered core
- Realms of Power: Faerie
- Realms of Power: The Divine
- Realms of Power: The Infernal *
- Realms of Power: Magic
- Apprentices
- Grogs
- City and Guild
- Art and Academe *
- Hedge Magic
Third category is what I consider saga resources. These describe the setting and how people behave. The content there may be used as inspiration to set the tone and the background for the saga. Any specific rules can be ignored by default, but the troupe may decide to use them as needed. Those would be:
- Guardians of the Forest (The Rhine Tribunal)
- The Lion and the Lily (The Normandy Tribunal)
- Sanctuary of Ice (The Tribunal of the Greater Alps) – even though it is a 4th edition book
- Faith and Flame (The Tribunal of Provence)
- The Church
- Lord of Men *
Fourth category is everything else. That content would be mostly for use by a storyguide to tell a specific story (or set of stories). Use by a player (for their own character instead of for a story) is subject to troupe approval.
(Note that I do not currently own the books marked by a *. I can purchase them if someone wants to use an important part of the book, but otherwise I am in no hurry to get those.)