This is not a particularly original idea.
I'm not sure if it first occurred to me after reading it elsewhere, but I do know that I have come across the same idea in similar forms on OSR blogs previously (the only one coming directly to mind is this one for using the table for Cleric "Miracles")
OK, so what does it look like...
(this is an edit from the table I originally posted which started the progression on level 1 as 9/11 which was perhaps a too restrictive for the poor MU)
I've adapted the Cleric Turning Table from Dyson Logos's Magical Theorems and Dark Pacts, because it slows down the progression somewhat and introduces a Destroy result as a roll earlier than it would normally become available.
How does it work...
- The Magic User must roll ≥ target number on 2d6 to successfully cast a spell.
- The Magic User pays a hit point cost for any spellcasting attempt, regardless of whether the spell is cast successfully or not. I'm planning on using this system with the Akratic Wizardry / Crypts & Things "Colours of Magic" system which uses the below costs:
- White Magic: 1HP + 1HP / spell level.
- Grey Magic: 2HP/ spell level.
- Black Magic: 2HP / spell level & corruption.
(Edit - this is probably too costly for uncertain spellcasting. I would modify this to either a lower cost [say 1HP/spell level] and/or only charge the cost for successfully casting [and possibly for casting fumbles]. The idea is to provide a limiting factor against the automatic success at higher level and also to make a use for the Destroy result, which I've used as no cost casting))
- The target numbers in parenthesis are the chance of casting spell with no HP cost. The magic User makes a single roll and takes the most favourable result.
- A roll of “2” indicates a fumble whilst spellcasting - roll again on the table.
- An “A” result indicates the spell may be cast automatically without rolling. If the Magic User wishes they may still roll to attempt to cast the spell at no cost, however this carries the risk of a fumble.
Why use it...
- I'm not particularly a fan of the Cleric and will likely remove it as a playable class - so if I'm going to kill it I might as well take its stuff.
- I dislike risk free / automatic spellcasting and haven't found a replacement system that works satisfactorily yet.
- Whilst it introduces uncertainty, risks and hit point costs to spellcasting it also provides the opportunity with some luck to cast more than your usual daily allotment / higher level spells than normally available.