Here are some thoughts about the Invisible Sling of Vilano, which is arguably one of the most dangerous offensive spells in the Ars Magica role playing game. These are meta-thoughts on the mechanics of spells, rather than actual spells which are direct boosts (you’ve been warned, heh).
I say arguably as the defense against the spell is trivial to accomplish for an experienced wizard who dedicates significant time to it, but impractical for most wizards, and the spell is wonderfully effective against creatures with high resistance to magical attacks. Frankly an opponent who has high magical resistance and also a high soak is darn powerful and is not meant to be fought head on without planning. Ars Magica is a story & discussion (at length) rpg and high challenge beasts should not be knocked down by a single style of attack. It would be the same in any game, but particularly so in Ars Magica as it does not make for compelling stories.
(a) Have you tried Multi-casting?
Simply put Multi-casting with Mastery is far less contentious because this is exactly the style of spell that should directly benefit from multi-casting, and it is the core rules. Use it. In fact this is really the go-to way to gain the maximum bang for your XP once a spell has been mastered.
Some troupes will limit or curtail the power of multi-casting, and that’s the troupe choice – I’m not a fan of that option, but it’s fair if applied equally and stated up front. There are so many ways to be an effective combat wizard in Ars Magica that it shouldn’t be a problem.
(b) Can the damage scale or stack?
Well maybe. Strictly speaking the rules are not definitive.
The ways that a Rego Terram spell like this could be improved is very particular to the style of the group playing Ars Magica. Opinions are divided in the discussion forums, although they do lend themselves toward one interpretation. The opinion was tending toward limiting the multiplicative power of concurrent iterations of a spell in spell designs (to be clear, you don’t just add more versions of an effect to increase the overall damage). Other players seek to allow stacking effects for increased damage output in a very linear way.
I’ve seen it called modifying the “base effect” vs modifying the “effect usage”. That makes a kind of sense, such as the difference between a large fire spell and a small one using a different base 10 or base 25 (variations on Pilum of Fire or Ball of Abysmal Flame), and also fire effects that use a Target: Group to increase the area of damage (Arc of Firery Ribbons). Both are legit.
There are two general approaches, each with variations, depending on how the troupe treats a change from Target: Individual to Target: Group – which in RAW is essentially allowing 10x times the material to be manipulated by a spell. Note too that many troupes will dismiss all these options as munchkin-isms.
- The 10x increase in the volume of thrown stones requires each throw to be aimed individually and damage to be resolved individually. This means 10x targeting rolls and 10x damage rolls, each doing +5 damage. This results in the spell being far more powerful and inflicting dramatically more damage due to how many more opportunities the spell has to hit and roll a high damage result.
- As (1) above, except the targeting rolls are made per target, and the damage is still inflicted per effect. This is a better option for speed of game-play, but sacrifices the opportunity for spray effects.
- As (1) above, except that targets with a soak/toughness +10 points or more above the +5 damage (so soak +15 or higher in the base example) brush off the damage without actually resolving the dice rolls. This mitigates the threat to targets with high soak. Tough characters stay tough, but softer targets are still significantly threatened.
- As (2) however a penalty applies for splitting the targets. This approach dictates that one primary target is chosen and trying to split the spell to target two different foes is very difficult,and suffers a Finesse targeting modifier.
- Allow the 10x fold increase to inflict damage once for each target, which inflicts more damage using a scale of how many stones struck each target. The scaling chosen really makes of breaks the approach, and scaling is dangerous (very ill-favored). Linear scaling: 1 stone +5 damage, 5 stones +10, 10 stones +15. Pyramid scaling: 1 stone +5 damage, 3 stones +10, 6 stones +15, 10 stones +20 damage.
Which to choose is up to the troupe. It is worth noting that going beyond 10x stones with a spell is certainly possible, but will not be practical in most scenarios as the raw materials are not present to fling so many rocks around.
(c) Increase the base effect guideline to make new versions?
Well I hope it can, as that’s what this spell does – a vicious version of Vilano’s Sling.
The RAW mechanics allow for damage to scale with the base effect, and that an increase in the size of the projectile make no significant change in the damage. Therefore a good design keeps the stones to fit sized as:
- Base 5, +5 damage
- Base 10, +10 damage
- Base 15, +15 damage
- And I assume this can continue just like the Ignem damage increments.