Tuesday, November 23, 2010

Critical Hits and Fumbles for Spells

More on the magic system I am in the process of developing.  I am implementing a roll to activate the spell.  Meaning no more automatic successes for magic-users who want to whip out a spell.  Spells will have a difficulty level depending on their level and other circumstances will effect the roll.  A quick note before I go on, my system uses spell points to determine if a magic-user is able to cast a spell therefore if a 1st level mage has learned the spell and somehow acquired enough points to cast a 6th level spell he may do so.  Here is the run down of difficulty levels (DL) and what would enhance the outcome.

0-level - 8 D, 1st level - 10 DL, 2nd level - 11 DL, 3rd level - 12 DL,
4th level - 13 DL, 5th level - 14 DL, 6th level - 15 DL, 7th level - 16 DL, 8th level - 17 DL, 9th level - 18 DL

- For every level of the magic-user get +1 to the roll.
- Caster adds his intelligence bonus to the roll.
- Spell specialization bonus.
- The caster suffers -1 to the roll for every point of damage taken during the combat.
- The caster suffers -1 for every spell he is maintaining.

A 1 is always a failure and a 20 is always a success.  Each spell has a critical failure or success result.  In case of a regular failure the spell points are expended, but the spell does not discharge.  A success and the spell goes off as planned.

The other wrinkle I put in is that mage's need to hit with their spells.  Not automatic hits with missile weapon or even a placement of a fireball.  He must roll 'to hit'.  So a mage may have critically succeeded in casting a magic missile, so its charged up to do max damage, it still needs to hit its target.  When mage attacks with a spell he gains his level and intelligence bonus (like in the roll above) to hit.  But it is possible to critically succeed on casting the fireball and maxing out the damage, but if the mage fail's to target it correctly it could explode at the party's feet.  Magic is fickle what can I say.  And as for any roll, the 'to hit' roll can have a critical hit or miss.  A critical hit with a magic missile may cripple the limb it hits, knock a person prone if it hits the chest, or knock a person out if it hits the head.

Like I said, its a process and something I still need to playtest.


  1. It's a good system if you want to nerf mages. Otherwise, not so much. Consider what happens to a low-level mage trying to cast magic missile: he has three opportunities to fail per casting: 1st he might not get the spell to go off, 2nd he might not hit, and finally, he might roll terribly on damage. If a magic missile does 1d4 damage, his expected damage from casting it the regular way (autocast, autohit, roll damage) is 2.5. Assuming that your chart means he has to beat 10 to cast a 1st level spell (and assuming that he's 1st level and has a +1 int bonus), and assuming that he has a 80% chance to hit, that makes his expected damage only 1.6. If he had only 50% chance to hit, his expected damage would be only 1. Even if he has enough points to cast each and every round, he'd be better off throwing stones. And that's before you figure in the chance of friendly fire, which would add in negative expected benefits.

    In the optimal case (only fail on an automatic, only miss on an automatic) spells are only about 90% as effective as in the usual system; in what's probably the typical case (75% in each), they're 56% as effective. Less if you still plan to allow monsters to save (if the monster saves 25% of the time, the 56% drops to 42%).

  2. BTW, I actually do use a rule where the mages need to roll to succeed, but they either roll to succeed, or roll to hit, or the monster gets a save, depending on the spell...they never have to succeed at multiple rolls in order to accomplish something. Generally spells that directly damage need a to-hit, spells that directly affect the monster in some other way (such as charm) allow a save, and spells that alter the environment (such as wall, or knock) require a casting roll.

    And if the spell requires a casting roll, failure costs them 1 spell point, not the full cost.

  3. The system I am developing for example a magic missile does 1d6 and the mage has the ability to pump more spell point into it to increase the damage. So in that way a mage has some control over the damage. I don't see it as nerfing at all, but more challenging, but potentially making a more powerful caster than in normal games.

    An example of this is if the class choosen was battle mage, he will have specializations in damage dealing spells. It will cost him less to cast and he gains bonuses to damage.

    If a normal 1st level mage casts a magic missile he does 1d4+1 damage (I think). In my system the standard damage is 1d6 plus a 1st level battle mage could pump it up to be +1 (the amount a mage can increase the damage is equal to his level) and add his intelligence bonus to the damage which could be +1 to +5. So the first level battle mage can possible to 1d6+6 damage. And if he has enough spell points he can still cast.

    But I do understnad your point and the reason I need to playtest it. My intention is not to nerf, but to give the player options.

  4. Multiple points of failure doesn't add options, just frustration as apparent successes turn into failures, particularly since once they decide to cast they have no influence over the die rolls. You really should consider reducing it to a single roll, and then adjusting that roll to get the success rate you want. That is, if you really want a mage casting a spell that's about his current power-level to have a 56% chance of success, just tweak the casting roll, don't make him roll casting and to-hit (and then potentially give the monster a save).

    If the goal is to give the mages more choices, I'd recommend letting them make decisions other than how much of their power to risk. For instance, you could maybe let them put extra power in to up their chance of success on the casting roll, or take a minus to the damage to "spread" the effect but up the chance on the to-hit. Or maybe you could allow them to "take 10" but only if they don't pump extra damage in, and only on spells below their current level.

    On a slightly different point, it's wise to be cautious about criticals and fumbles. Since they're involved in all the battles, the PCs are going to be on the receiving end of a lot of criticals in their careers, and commit a lot of the game's fumbles. Unless you explicitly make the rules different for PCs and NPCs, even a 1 in 1000 chance of TPK from an enemy spell crit or your own fumble means that's probably how your campaign will end.

  5. I've always felt that there was not enough ROLE playing when it comes to casting, few players actually incant and fewer still make their own spell books.

    I tackled this by making a verbal component mandatory in order to cast. Although spell's are still automatic it gives me DM's license to modify the effect up or down slightly depending on how well the incantation was delivered. This has gotten me out of a few jams and created some really tense situations where the party had to rely on the normally tongue tied mage to save the day.

    Coming up with the incantations is a player responsibility, as is making a spellbook. The length and complexity of each is down to the player but I ask for a minimum of 1 line per level of spell.

    The main difference is in how it makes the players react when they are in unfamiliar environments (underwater, in total darkness, flying.

  6. Another question about your proposal: Under 1e charts, Wizards normally get to cast 9th level spells at 18th level. According to your post, they would have a bonus on the casting roll of +18, and 9th level spells have a target of 18. So... unless they roll a 1, they will always succeed, even with the most difficult spells? Maybe you could change the bonus to +1 per 4 or 5 levels; i.e. +0 for levels 1-4, +1 for levels 5-9, +2 for levels 10-14, and +3 for levels 15-19.

    I like Joshua's idea of one roll for spell successes (to cast, to hit, or target to save). I'll definitely include that in my campaigns.

    I've been thinking about how to offer more variety to Wizards also, but I've decided that (for me) spell point systems seem to end up being more bookkeeping (and fun-killing) than they are worth.

    One idea I had was to make Wizards more like Sorcerers: if they "know" a spell (it's in their spellbook, etc.), then they can cast it without having to declare that they "memorized" it that morning.

    Another idea was to base spell advancement on spell schools (like from 3.5e), but without opposing school restrictions. Under this idea, if a 1st level Wizard chooses "Evocation", then he "knows" and can cast any 1st level Evocation spell. When he gets to 2nd level he chooses another school, say Abjuration, so he can cast any 1st level Abjuration spell. At 3rd level he would have to choose to be able to cast either 2nd level Evocation or Abjuration spells. He couldn't choose a different school, because he hasn't yet learned the 1st level spells for that school. This idea gives Wizards a huge range of spell choices each day, but doesn't really change the game "balance", or require any additional work on anyone's part. And while there are no school "restrictions", if we use the 1e spell advancement charts (which I do), then they will still only know 6 schools at 26th level (beyond what many campaigns even get to).