I’m introducing a group to Ars Magica—they’d all heard of the game but not played it. Two out of three of this group are generally more comfortable with storygames, and one of them was primarily interested in Ars Magica because of the shared/rotating GM structure. After our first session, they asked if it would be possible to have a flexible free-form magic system like Ars Magica in a Powered by the Apocalypse game.
I of course immediately said ‘no’, because PbtA doesn’t have difficulty levels, and doesn’t even really have rated skills in most iterations. Generally, either you can do a thing or you can’t, and if you can do it you do it just as well as someone else does.
Every PbtA game I’m aware does have a small set of stats, usually 4-8, that differentiate characters, but these generally vary just by a couple points (frequently ranging from -1 to +2), and they often only change within that range (rather than potentially increasing overall over time).
And without skills to differentiate wizards’ magical abilities, the feel of Ars Magica would be lost.
But then I got to thinking.
There would need to be skills to differentiate different kinds of magic. That’s the key thing that distinguishes Ars Magica from other magic systems. But make the skills too big, and it overwhelms the 2d6 roll. But we need to have a range of skills to differentiate the spells, or there’s no point in having the separate skills.
So here’s my idea:
- Change the basic roll from 2d6 + attribute to 2d6 + attribute + skill – difficulty.
- Results are still 6–, 7-9, and 10+.
- And, copying Ars Magica, magic skills are always paired, a Technique (verb) and Form (object). So when using magic, the roll becomes 2d6 + attribute + Technique + Form – difficulty.
I don’t think we need to preserve the extensive skill list of Ars Magica. The ones that tie into magic should become moves. Probably turn a lot of the knowledge skills into moves, too, since “knowing stuff” is a pretty wizardly trope. And, of course, the Houses become our playbooks. The key Virtues & Flaws tie into the playbooks, and any other important ones are treated as advanced moves.