Introducing Magic into Cthulhu d20

[Narfellus]

I'm running Masks of Nyarlathotep for my group and they just reached 2nd level and made it to the London scenario. On the way over, the bookseller character studied Africa's Dark Sects and learned Create Corpsewalker, and then made a series of checks to read a Latin version of Vermiis Mysteris. I sort of coddled together the Chaosium rules and d20 rules and figured it would take him about 6 months to read the Vermiis, and then he has to beat a DC 24 to fully absorb it. After that, he still has to research the spells individually which can take weeks apiece.

What spells should i include? I already hinted to him after he skimmed the book (he has 1 rank in Latin) that it had to do with summoning beings from other worlds and planes, and that it could be very dangerous. I'm not sure exactly which magic system i am going to incorporate into the game. d20 does the ability point damage and SAN damage which is pretty harsh. In fact, i think that is scarier than the simple MP pool from Chaosium's system. But then i've also been fooling around with the idea of having spellcasters make casting checks for every spell, just to see if it works correctly. Critical failures can have really nasty side effects, and plain failures can still drain your abilities (or MP). I was considering having a MP pool equal to his WIS score, but then i don't want him to have that recharging pool AND the default d20 rules with ability score damage.

unless...

Using the ability point drain ensured success at casting the spell, but using the MP pool demands a caster check every time you use that route. It might give them too much magic though, i want to keep it pretty low key, with him wondering if he should risk casting a spell or not. Any suggestions?

 

[Bagpuss]

Elder Sign is always a good one, but you want to keep its 1 Permenant Con Drain, since they had that in Chaosiums edition as well.

Don't forget most of the spells the attribute damage is only temporary. Its the sanity loss thats more of a concern, but investigators really shouldn't be using magic except in the most dire situations.

So far my player's have learned.

Create Bad-Corpse Dust, although it is modified from the version in the book and not known by that name. Elder Sign and Summon/Bind Star Vampire (also known by another name).

They have cast no spells so far, this has more to do with the in game conditions of the spells, like finding animate corpse intestines and biting your own flesh off than the attribute drains/damage.

I'm having to keep a log of who's read which books (Full Sanity Loss & Mythos ranks), and who just scanned through them (initial Sanity loss only), and who's actually learned spells. They have four mythos works in their collection, but have seen several more, all of them have completed at least one book, but only two players have learned spells.

You also need to keep track of who's been driven insane by exposure to mythos as they get +2 ranks, and then another +1 rank for each following occasion.

 

[Keeper of Secrets]

I shall second Bagpuss. Elder Sign is really kind of a must for characters in a long lasting Cthulhu game (or it may not end up being very long lasting if you know what I mean). Of course, if you really want to give them a sense of purpose you could let them know Elder Sign is available but make them wait in suspense for a few sessions to learn it.

 

[Bagpuss]

The protective spells are usually the better ones to give out. Also don't let the players read the discription in the book, take the discription and attributes as inspiration then type out a sheet that reflects the ritual required. This is particularly true for the spells that have been ported from D&D and lack any interesting requirements.

Adding in requirements of blood sacrifices, weird material components, chanting in foreign/alien languages, etc. Makes it less like the cookie cutter magic you get in D&D.

The offensive ones tend have nasty costs involved, that are easily offset if you are already an insane cultist, but really make it unlikely a PC will use them. Of course sometimes letting them learn these presents them with an interesting choice to make.

 

[Narfellus]

Yeah, great ideas there. I will definitely mete out the spells slowly, and be sure to make them as non-DnD as possible, with grisly components and ghastly side-effects. Gotta love Cthulhu...