How it works
First, if you aren't familiar with Wonder & Wickedness I'd suggest reading up a bit on it (hell go buy it, its fricken awesome).
As per traditional Vancian casting the Magic User prepares a number of spells per day in their memory (say level + INT). However the casting of the spell requires a casting check - if the spell is successfully cast it is not lost from memory, however each successful casting accumulates Arcane Stress, making further checks harder. The Magic User may elect to wear and cast in armour, however the casting check is penalised. Further, the caster may elect to incur Spellburn, suffering hit point damage to increase the likelihood of successful casting. The uncertainty in casting is balanced by increased flexibility and the potential to cast more spells than via the normal class progression. Rather than the number of spells that can be prepared per day, Arcane Stress and hit point loss through Spelburn become the primary resources for continued spell casting.
Casting check: 2d6 + Casting Bonus - Arcane Stress - Armour Casting Penalty + Spellburn
Casting Bonus: +1 per caster level + Intelligence bonus
(I would recommend using the B/X modifiers for 1d6 and 2d6 rolls: INT 3: -2, INT 4-8: -1, INT 9-12: no modifier, INT 13-17: +1, INT 18: +2)
Arcane Stress: -1 penalty to casting that accumulates with each successful casting. Arcane Stress may be recovered by a nights rest
Armour Casting Penalty: penalty to spell casting equal to AC bonus from any worn armour/shield
Spellburn: caster sacrifices their vitality to increase the power of their casting - nominate number of hit points to burn and receive the same number as a bonus to the casting check
In addition to the total casting check, the natural dice roll also effects what can happen, representing the vagaries and risks inherent in wielding magic. Any roll of doubles indicates a wild surge of magic
Roll is doubles (odd): caster suffers backlash - regardless of casting result caster incurs 1d4 (exploding) points of Arcane Stress and any Spellburn is doubled
Roll is doubles (even): caster channels surge - regardless of casting result caster recovers 1d4 (exploding) points of Arcane Stress (this can result in a temporary positive Arcane Stress modifier which is retained until spent or the caster's next long rest)
In some circumstances the caster may lose control of their spell and rolls on the Spell Catastrophe table (in Wonder & Wickedness) for the matching spell school. Spell catastrophes occurs when:
- Casting check result is: Failure (Major) or Failure (Minor) and Arcane Stress > Casting Bonus
- Casters hit points are reduced to 0 whilst casting (including from Spellburn)
Favourable and unfavourable casting conditions
If the DM deems that the conditions for casting are particularly favourable or unfavourable they may rule that the caster has advantage or disadvantage on their casting check.
- Caster is in a calm environment, has surplus time and can read from their spell book.
- Caster has access to special material components (big ass diamonds, captured souls, eye of gargantuan undead newt), special casting location (conjunction of ley lines, earth node) or special casting time (triple lunar eclipse, solstice / equinox)
The caster may roll 3d6 and take their preferred two rolls for their casting check. Wild surges are also less likely, occurring only on double "1" or "6"
- Caster has been damaged (not including spellburn) or interrupted whilst casting - a casting check which was originally a Success (delayed) applies the new result.
- Caster has lost spell from memory but wishes to attempt casting it again
- Caster is attempting to cast a spell they do not know but have access to from a spell book
The casting check is rolled using 3d6 with the worst two rolls applied. Any roll of doubles other than a "6" is considered a backlash Wild Surge result.
Material components and casting talismans
Whilst it can be assumed that some form of material component may be involved in casting, this system opens the possibility of "special" components which increase the likelihood of successfully casting a spell. Rare and expensive components and corrupting or illegal rituals (e.g. sacrifice) could be used to grant a bonus to the casting check. This could also achieved by the crafting of minor one use magic items (magic items which provided a permanent bonus would bring a significant power boost and would be better perhaps tied to certain schools or even individual spells). I haven't thought too much about specifics but there is a lot of potential here for adding flavour, providing adventure hooks and offering more options for magic users to spend their hard earned (stolen) cash on.
Maleficence and Spell Defence
Wonder & Wickedness includes the option to expend any prepared spell for Maleficence (generic damage dealing spell) or Magical Defence (protect 1 person / caster level from a damaging spell effect). These would be still be available using this system. Consider them to be the same as any other spell only they do not need to be prepared and cannot be lost from memory following a failed casting check. An option for Magical Defence would be to modify the casting check by (level of caster attempting to defend - caster level of attacking spell).
Changes from inspirational material
In Brendan's system Arcane Stress occurs on a failed casting check. I've changed this to on a successful casting for two reasons - so as to not double penalise failed rolls (arcane stress + lose spell from your memory) and also because in Brendan's system once bonuses to casting check get to a certain point the check will not ever be failed
Spellburn was inspired by DCC, however I have simplified it to hit points rather than ability scores (as this just makes more resource pools to keep track of)
Given Brendan is the author of W&W and has also tinkered a lot with 2d6 casting rolls, Im very curious as to what he may have done with them for W&W.