Spellcasting Chaos Table
When I’m playing adventure games I want magic to feel strange, mysterious, and unpredictable. Even the most powerful wizards should approach magic with caution, because they know that the forces they’re invoking are beyond their control. That caution should be magnified for less studied/experience characters.
I want a supplementary rule system that you can add to any adventure game that introduces chaos spellcasting while honoring character experience.
Proposal: When a character casts a spell, they roll 2d6 and lookup the result on the following Chaos Table:
| 2d6 | Result |
|---|---|
| 2 | Catastrophe: The spellbook is destroyed; 1d8 blast damage to caster* |
| 3-4 | Failure: No effect |
| 5-9 | Success: Works as intended |
| 10-11 | Enhanced: Increased intended affect |
| 12 | Chaos: Increased unintended affect (roll random spell)* |
*: Player can make a saving throw to avoid the affect
This table introduces unpredictability to spellcasting by adding the chance of various failures and successes. With these consequences, players will need to decide if it is worth the risk to cast a spell.
Examples
- Cast “Astral Prison” and roll 2: The player’s spellbook is destroyed, and they and all creatures around them receive 1d8 damage. The player can make a saving throw to avoid the damage.
- Cast “Beast Form” and roll 4: The player expends the cost of the spell, but it fizzles and has no effect.
- Cast “Charm” and roll 7: The spell works as intended.
- Cast “Leap” and roll 10: Instead of leaping 10 feet, the player easily leaps 20 feet (or more).
- Cast “Miniaturize” and roll 12: Instead of shrinking, the creature turns into a gelatinous ooze (random spell). The player can make a saving throw to avoid the affect.
Cairn spellcasting
While working on this proposal, I re-read Cairn’s rules for casting spells which uses a more narrative-driven approach:
Given time and safety, PCs can enhance a spell’s impact (e.g., affecting multiple targets, increasing its power, etc.) without any additional cost. If the PC is deprived or in danger, the Warden may require a PC to make a WIL save to avoid any ill-effects from casting the spell. Consequences of failure are on par with the intended effect, and may result in added Fatigue, the destruction of the Spellbook, injury, and even death.
I like this system, but I think my proposal is intriguing because it introduces the possibility of unintended consequences even in ideal conditions. With the Chaos Table, magic is not neat and tidy but wild and dangerous.
To mimic the “deprived or in danger” situation, you could add a -1 penalty to the roll or swap one of the d6s for a d4.