Anyone integrated Call of Cthulhu style magic into D&D?

[Cheiromancer]

mmadsen's idea seems to be a good basis for a conversion. I'm not sure that the Spellcraft roll is the way to go. I'm not sure you'd want every expert to have skill focus: Spellcraft. Or have some (low-level) spells be risk-free.

Incidentally, does anyone have any idea how Vancian (spellslot) spells can be converted into Cthulvian (attribute drain) spells?

The conversion of Cthulvian to Vancian spells does not seem to be according to any general rule.

[edit]

Divination and mind affecting stuff generally costs Wisdom. Strength is for stuff that does direct damage (and control weather, and a couple of other things), most everything else is costs intelligence points.

Sanity recovery in CoC is around 1 point a month, maybe 2 or 3 in ideal conditions. DnD style heroes might bounce back faster, but probably still only 1 point a week. Provided they haven't lost any Sanity in that week. Maybe 2 per week if in restful, peaceful conditions. Could work for a campaign if there is 6 months or a year between adventures.

Now, how to determine what the San and Ability costs are? I'm have tempted to assign them randomly.

[/edit]

 

[mmadsen]

I'm not sure that the Spellcraft roll is the way to go. I'm not sure you'd want every expert to have skill focus: Spellcraft.

If you're willing to do a little work, you can associate different spells with mundane skills and not just Spellcraft. For instance, Enchantments could rely on Bluff and/or Diplomacy, many explosive Evocations could rely on Alchemy, Druid spells could rely on Wilderness Lore and/or Knowledge: Nature, Bard spells could rely on Perform and/or Diplomacy, and so on.

Perhaps you'd have to make a Spellcraft roll and one other skill roll. Or just roll against the worse skill.

The conversion of Cthulvian to Vancian spells does not seem to be according to any general rule.

There doesn't seem to be a clear level-to-cost relationship. You could just ditch the CoC examples and come up with your own level-based costs, e.g. one Sanity per level (half with Spellcraft check), two points from one Ability score for every two levels.

Sanity recovery in CoC is around 1 point a month, maybe 2 or 3 in ideal conditions. DnD style heroes might bounce back faster, but probably still only 1 point a week. Provided they haven't lost any Sanity in that week. Maybe 2 per week if in restful, peaceful conditions. Could work for a campaign if there is 6 months or a year between adventures.

To borrow an idea from Conan, perhaps wizards recover Sanity by meditating under the influence of soporific lotus blossoms?

 

[Cheiromancer]

To borrow an idea from Conan, perhaps wizards recover Sanity
by meditating under the influence of soporific lotus blossoms?

Ooh! That's an awesome idea!

 

[mmadsen]

Ooh! That's an awesome idea!

Thanks, Cheiromancer!

Another (only slightly related) idea is to replace Experience Point costs with Sanity costs.

 

[Kaptain_Kantrip]

Cthulhu uses both XP and Sanity costs (though only a few spells have an XP cost).

I've been using Cthulhu magic and Sanity "as is" (having removed all other magic systems, though some D&D spells were converted over) in my d20 game and it is working nicely. Magic is terrifying and alien, and everybody who knows even a lousy cantrip is afraid of casting it because it will cost them a Sanity point to do so. Seeing monsters costs Sanity points. Seeing dead bodies costs Sanity points. Reading crumbling tomes of eldritch lore (spell books) or bargaining with "demons" to impart such lore directly costs Sanity points. The game is much more scary and mysterious now. Try it. You'll like it!

Sanity Gain:
Level gain: +1d6 Sanity Points
Story/Mission Objective Award: +1d3 Sanity Points
Per month of private care and rest: +1d3 Sanity Points

 

[mmadsen]

I've been using Cthulhu magic and Sanity "as is" (having removed all other magic systems, though some D&D spells were converted over) in my d20 game and it is working nicely. Magic is terrifying and alien, and everybody who knows even a lousy cantrip is afraid of casting it because it will cost them a Sanity point to do so. Seeing monsters costs Sanity points. Seeing dead bodies costs Sanity points. Reading crumbling tomes of eldritch lore (spell books) or bargaining with "demons" to impart such lore directly costs Sanity points. The game is much more scary and mysterious now. Try it. You'll like it!

You sound like some kind of Harn snob.

Seriously though, do you have any anecdotes from your game?

 

[Kaptain_Kantrip]

You sound like some kind of Harn snob.

Seriously though, do you have any anecdotes from your game?

Well, the witch PCs only know a handful of cantrips (none have any visible "magical" effect when cast). Each cantrip costs 1 Sanity point per casting. Starting Sanity is equal to Wis score x 5.
Factor in Sanity loss from seeing dead bodies, monsters and nightmarish visions from beyond on top of Sanity loss from spellcasting, and you can see why they don't cast many spells!

Note: I'm using a mix of Psi HB 0 level powers, Cantrips and Orisons for their spell list possibilities.

So, in three sessions, each witch (2) has cast roughly an equal number of cantrips and lost an almost equal number of Sanity points from encountering things they shouldn't, LOL. In the first session, each cast 1 cantrip (missive) so they could communicate with each other through a wall and coordinate their sneaking out into the woods to see the "crazy woman" in the woods for advice... Okay, that's not bad, considering she could have cast more cantrips to 1) cushion falling damage from a tree climb (catfall from PsiHB), and 2) heal 6 hbit points of damage from said fall via cure minor wounds applications. Instead, she chose to take the damage rather than lose Sanity. There was no combat involved in the first session (all RPing/orientation/investigation).

Next session, they cast one cantrip between them both! Don't remember which one. Again, no combat (all RPing/investigation).

The third session, they finally met a demonic creature, found a hideous mummified corpse, inhaled mystrical vapors that induced nightmarish visions and lost about 9-12 Sanity points each just from that (no spells yet!). During and after the battle with the "demon" (they ran away the first time they saw it!), they cast about ten cantrips each (one daze cantrip, one inflict minor wound/ranged, and the rest all being cure minor wounds to bring everyone back up to 1 hit point each if they had less).

They made second level and I gave 2d6 bonus Sanity for that, let them pick another handful of cantrips, and 2d3 bonus Sanity for accomplishing two story goals (tracking the demon down to its lair and killing it and recovering the crazy woman's stolen spellbook). The demon was a CofC Spectral Hunter (invisible, incorporeal monstrous humanoid that turns others invisible to enhance their fear and confusion before killing them). The party almost died, in fact, only one witch was up, and at 1 hit point, when she figured out she should crush the demon's "soul object" (clay likeness).

So, that's it so far. They returned the spellbook (but both are illiterate peasants) and have the opportunity to learn literacy and eventually more powerful spells if they do the crazy old hag's evil bidding, LOL. If anyone finds out they have magic powers, they will be burned at the stake (after being tortured for confessions and to find any accomplices).

The thing is, magic is not limited by castings per day or level. Cast as many spells of differing power levels as you want (if you can pay the cost). The choice is the players... but if they do, they will quickly go nuts or get killed, or both. Having that power is at once liberating and terrifying to players. They must carefully weigh the cost of doing things the "easy way" (with magic) or the "hard way" (without). With great power comes great responsibility! Most will use their "gift" sparingly, and with minimal magic (except for dramatic effect in crisis situations in most cases), magic becomes much more alien, dangerous and mysterious. It really changes the mood and flavor of the game (for the better, IMO, but I'm an elitist Harn snob, so what do I know? )

 

[Kaptain_Kantrip]

Here is my current conversion system (using Sanity).

CONVERTING D&D SPELLS TO CALL OF CTHULHU
The costs in ability damage and Sanity of various D&D spells can be roughly estimated as follows:

0-Level: 1 Sanity point.
1st-level: 1d4 Sanity points.
2nd-level: 2 Str, Con, Int or Wis damage and/or 1d4 Sanity Points.
3rd-level: 3 Str, Con, Int or Wis damage and/or 1d6 Sanity points.
4th-level: 4 Str, Con, Int or Wis damage and 1d8 Sanity points.
5th-level: 4 Str, Con, Int or Wis damage and 1d10 Sanity points.
6th-level: 6 Str, Con, Int or Wis damage and 2d6 Sanity points.
7th-level: 10 Str, Con, Int or Wis damage and 1d20 Sanity points.
8th-level: 10 Str, Con, Int or Wis damage and 2d10 Sanity points.
9th-level: 20 Str, Con, Int or Wis damage and 3d10 Sanity points.

Making Spells Permanent: Most non-instantaneous spells that target a creature can be made permanent in duration or until a specified condition is met (such as a curse). To accomplish this, alter the ability damage of the spell to permanent Con drain (1 point for 4th level spells or under, 2 points for 5th to 8th-level spells, and 20 points for 9th-level spells); increase the Sanity point cost to the next higher level (so a 5th-level spell made permanent would do 2d6 Sanity points rather than the normal 1d10.


USING THESE RULES WITHOUT SANITY
Change Sanity to "Aura" (representing life force/soul). All characters receive a starting Aura score at 1st level equal to Charisma score x 5. Bonus Aura points are 1d6 or 2d6 (DM's choice) per level gained, plus 1d3 per story/mission goal accomplished). Max aura = 99 minus character's combined Knowledge: Arcana and Spellcraft ranks. Any Questions?

 

[mmadsen]

0-Level: 1 Sanity point.
1st-level: 1d4 Sanity points.
2nd-level: 2 Str, Con, Int or Wis damage and/or 1d4 Sanity Points.
3rd-level: 3 Str, Con, Int or Wis damage and/or 1d6 Sanity points.
4th-level: 4 Str, Con, Int or Wis damage and 1d8 Sanity points.
5th-level: 4 Str, Con, Int or Wis damage and 1d10 Sanity points.
6th-level: 6 Str, Con, Int or Wis damage and 2d6 Sanity points.
7th-level: 10 Str, Con, Int or Wis damage and 1d20 Sanity points.
8th-level: 10 Str, Con, Int or Wis damage and 2d10 Sanity points.
9th-level: 20 Str, Con, Int or Wis damage and 3d10 Sanity points.

So far you've only had the players cast a few 1-Sanity cantrips though, right?

 

[Cheiromancer]

I think there should be some way of working xp into all this. You could pay xp to get back some lost sanity when you level up. Or pay spells with xp instead of sanity. Something like that.