I've been looking for a good system for a magic user focused campaign. Medieval fantasy or modern. I tried Mage the Ascension since I like the flavor of the magic system, but I just got frustrated with the rules and also by the lack of good pre-written adventures. I would love to play in a MtA game, but hated trying to run the game.
Can someone who has played Ars Magica explain some of the core mechanics, especially regarding casting, or link any good summaries or reviews?
Also, how tied into the setting and lore is Ars Magica? Could I run a game in a home brew world, or would that be taking away a lot from the game?
Lastly, is there enough published adventures for the system to run a campaign of at least a few months? How well designed are the adventures?
Ars Magica uses a D10 roll for everything. It can be rolled as a simple die, reading the numbers 1-10 (0 counts as 10), or a ‘stress' die which is read 0-9. When rolling a Stress die, a 1 allows for a double die roll to be added to the score, but rolling a 0 counts as ‘0’ with a potential ‘botch’ die then rolled to see if it was a catastrophic failure (if you roll another 0). Depending on the stress level of the task you can increase the number of botch dice you roll.
The core mechanic is Stat + Skill + die roll vs Target number which goes up with difficulty.
Magic also operates like this, except you add Stat
+ Verb + Noun vs the casting level of the spell. Spells can be
designed where you have scores in 5 different techniques (verb) and 10 different forms (noun) which you can combine to create effects. So, for example, you could have a score in Creo (“I create”) of 8 and a score of Ignem (“Fire”) of 7 and combine them to cast a level 25 fireball spell where you roll 8 + 7 + stress die vs a 25 target. The higher the level of the spell the more powerful it gets. However, casters can also create spontaneous magic rather than use a formulaic spell by casting at a fractional level below their magic score totals.
The first edition didn’t have any setting, so the Mythic Europe Setting is one that has been developed over several decades and is based on very well researched historical Europe but with a mythical fantasy overlay. It is basically a magical version of history where the superstitious beliefs are real. It is, however, entirely optional - you can set the Order of Hermes in any fantasy setting with little trouble.
There are something like 40 published supplements that are now available in POD. These include lots and lots of adventure and campaign material. Atlas Games maintain a forum on their site which is still active and some gamers play Ars Magica exclusively for years. Its entire set up is for long term, extended play and the main ’splats’ are geographically based Tribunal books. There are some books with a good range of adventure anthologies though.
You’ll also note there are three tiers of play - Mages (which are powerful), Companions (which are advanced, independently thinking non-magical characters) and Grogs which are basically servants and guards, but you can still make them individually interesting to play in low key games. All live together collectively in a Covenant that the players collaboratively design together.