Resisting spells with Active Defense "saving throws"

[Ejidoth]

An idea I've been contemplating as a tweak to the baseline Magic system is, instead of a quick contest, to have such spells resisted with a 'saving throw'.

Stuff that's resisted with HT would instead give the victim an active defense of 3+HT/2 to resist. Stuff that's resisted with Will would give 3+Will/2 to resist. That kind of thing.

Deceptive attack style '-2 to hit per -1 to resist' might or might not be available. I'm not sure.

So! While I like this idea in principle, I'm curious what it would do in practice. Does anyone with a better head for system-math and probabilities have an idea of what the effects of this would be on a campaign, and how to balance it so it works?

I could just try it in my games, but I'm worried it might actually be wildly broken in some way and don't want to risk sacrificing an ongoing game for it.

[Taneli]

It makes things a lot harder to resist, if that is something you want, sure.

[Taneli]

Oh wait, forgot about MoS. Let’s re-think.

Assuming a caster skill of 15 and an attribute of 12:

The usual way, if the caster rolls a 10, you effectively get -5 to your roll to resist, so you need to roll 7 or less to resist.

Your way, caster only needs to succeed on their roll to cast, and assuming a successful roll, you need to roll vs your Att/2 +3 or 9 or less to resist.

Actually it now looks like it’s easier to resist. Of course I have not crunched all the numbers yet. If we’re going to do that, we can ignore all failures for the caster, and presumably on your proposed way a critical success on the casters part would mean no chance to resist, or no?

[Ejidoth]

If the caster fails, he fails, just like any other spell. On a critical success, sure, it makes sense to skip defense just like attacks do.

I'd figured the basic odds (since casters tend to have high spell skills) will be very roughly on par.

I'm a little concerned about range no longer making spells easier to resist, but I'm not sure if it's a big deal. Basically, casters will usually have a penalty on their spell for range to the target, which makes resisting easier, but that wouldn't apply here.

I'm also still waffling on a deceptive attack equivalent. My gut feeling is that it probably either shouldn't be an option at all, or it should be capped at some penalty to defense (=Magery?), because allowing it to be unlimited creates the same problems that the rule of 16 is meant to prevent in the standard system.

[kirbwarrior]

A friend of mine when making a roleplaying system entirely threw out Quick Contests and uses your idea for everything. I really like it.

Originally Posted by Ejidoth

I'm a little concerned about range no longer making spells easier to resist, but I'm not sure if it's a big deal. Basically, casters will usually have a penalty on their spell for range to the target, which makes resisting easier, but that wouldn't apply here.

I'm also still waffling on a deceptive attack equivalent. My gut feeling is that it probably either shouldn't be an option at all, or it should be capped at some penalty to defense (=Magery?), because allowing it to be unlimited creates the same problems that the rule of 16 is meant to prevent in the standard system.

It might actually make it harder. You still have the penalty of range and the penalty of Deceptive Attack to worry about. And since DA already has a hard cap (can't reduce skill below 10) I think it's fine unless you still use the Rule of 16. Then again, unlike actual attacks they are always allowed to defend (there's never a 'no active defenses' against resistance).

Unrelated, I totally through Deceptive Attack had a max penalty of -10 to give -5. But I don't know why I thought that.

[Rolando]

Are you allowing advantages to add to it, like magical resistance adding to the defense? or making some enhanced defenses (like enhanced dodge, parry, block) without needing magical resistance?

Is there a way to use a skill to improve defenses, like weapons skills and parry?

[kirbwarrior]

Originally Posted by Rolando

Are you allowing advantages to add to it, like magical resistance adding to the defense? or making some enhanced defenses (like enhanced dodge, parry, block) without needing magical resistance?

Is there a way to use a skill to improve defenses, like weapons skills and parry?

I think things like Magic Resistance would add to the base attribute to help determine defenses (and it already decreases the spellcaster's roll).

[Pursuivant]

This is an interesting idea. It's highly suitable for certain fantasy genres where the target's ability to resist the spell is independent of caster skill or range. It certainly would make DF much more "D&D-like.

Originally Posted by Ejidoth

Deceptive attack style '-2 to hit per -1 to resist' might or might not be available. I'm not sure.

I'd only allow this option for Missile Spells or Melee Spells which are delivered using some skill other than the base spell skill. For Area, Blocking, or Regular spells, the act of casting the spell is a different action than attacking or defending, since a given spell might not actually be an attack or defense. In any case, spells can't benefit from AoA options.

OTOH, giving bonuses for various forms of AoA to rolls to avoid losing concentration might work. For example, the magical equivalent of AoA (Determined) might give you a +2 bonus to rolls to maintain your concentration while spellcasting.

Originally Posted by Ejidoth

I could just try it in my games, but I'm worried it might actually be wildly broken in some way and don't want to risk sacrificing an ongoing game for it.

Playtest it, either on your own or with players. Run a simple melee independent of your campaign with and without the new option. See how you and your players like it.

Neutral

* Target resistance is decoupled from caster skill and range penalties. This gives your average person a 50% chance to resist a typical spell regardless of caster skill.

* It penalizes casters with high skill casting Melee spells or close-range Regular spells.

* It benefits casters with relatively lower spell skill or who are casting Regular spells at a distance.

Cons

* Play might be slowed because you're decoupling the spellcasting roll and the resistance roll.

* Treating Resistance Rolls like an Active Defense seriously penalizes most people, since their resistance is based on Attribute/2+3 (average: 8) rather than just the base attribute (average: 10).

* Mechanically, it makes Magic Resistance a great deal as opposed to Enhanced Defenses.

[Anders]

You could base Will rolls on (Mental Strength or Mind Block)/2+3.

[Rupert]

Originally Posted by kirbwarrior

I think things like Magic Resistance would add to the base attribute to help determine defenses (and it already decreases the spellcaster's roll).

Magic Resistance currently adds to your resistance roll and subtracts from the caster's roll, so each level buys you +2 margin of success. I would have it grant a +1 to your magic defence rolls in this system, making it the magical equivalent of Enhanced Defences. It still wouldn't apply vs missile spells, because they get normal dodges, etc. as the defence against them already.

I think this will make lower skilled casters a bit more powerful, as their spells won't become next to useless in opposed rolls, and will as others have said give casters more effective range with opposed spells.

The question is how to determine margin of success for spells that use that to determine duration, etc.