Question re: Ritual Magic
 

So I'm working on a GURPS Ravenloft game, and I'm trying to interpret the magic of Halan Witches. I'm using Ritual Magic and Power Investiture, but I want each college of magic (which I'm rearranging, rather than taking the standard GURPS colleges) to use a focus.

The focus would be an item with the appropriate Gadget limitations, but does the limitation go off the cost of Power Investiture, or the cost of the various Ritual Magic college skills, or what? The focus is require to cast spells, but not just to being a Witch.

Also, I'm using other limitations such as Time Required, would these go off Power Investiture as well?

Thanks.

Re: Question re: Ritual Magic
 

Gadgets only reduce the cost of the advantage, not the skills used to use the advantage.

Re: Question re: Ritual Magic
 

Yeah, but since the caster needs multiple foci, one for each college, do I add up all the limitation bonuses, or just give a single bonus?

Re: Question re: Ritual Magic
 

Power investiture which represents the advantage rather then skills which represent the knowledge IMHO.
However if the focus is something that must be consecrated and specially built then I would put an accessability limitation on the power investiture and a gadget one on each college skill. Bit Munchkin though and if this was for a campaign and a standard rule then I'd call it a special effect and give it only to the PI advantage but maybe up it a bit if the foci required lots of preparation.

Re: Question re: Ritual Magic
 

Hmm... the latter could work. I don't think it'll be too munchkiny because of all the penalties you get on spells in ritual magic (just looking at Alter Visage, which as far as I can tell gets a base penalty of -15, ye gads), and not having skill rolls go above the Ritual Magic skill.

Thanks!

Re: Question re: Ritual Magic
 

First of all, how common are these focuses? Are we talking "To use spells of the Plant college, you must have a staff blessed by the Plant God personally", or "To use the Plant College, you must have an oak staff"? Because the Gadget limitations are only for the former. Gadgets must be objects that are rare, if not unique, in the campaign world. Basic explicitly states that Gadgets must be "items [that] are not for sale at any price in the game world." (Emphasis in original).
If the focus items are fairly easy to replace, then they warrant, at best, a -10% limitation if they're big, bulky, and hard to carry around. If they're easy to carry, they're -5%.

Limitations are never applied to skills.
Applying the limitation to Power Investiture means that it affects the bonuses Power Investiture provides. So, for example, if a witch has a spell that has no Power Investiture prerequisite to cast, then they could still cast it even if they lacked the focus - they just wouldn't get the bonus of their Power Investiture to skill.
If you want the actual spells to be limited to casting with a focus, you can just stipulate that that's how the ritual magic works in your world. The game supports this quite easily, no need to limit the skills.

Again, if you limit Power Investiture, you only limit the bonuses it provides. It won't limit the spells themselves. So if you have Preparation Required: 1 minute on Power Investiture, the witch will have to pray, chant, or whatever for a minute to get the bonus that Power Investiture provides, but if they have any spells that could be cast without Power Investiture, they can still cast them. Also, don't forget that Preparation Required applies every time you use the limited advantage. So if you put a 1 minute prep time on Power Investiture, a witch would need to spend a minute preparing for every spell.

If you just want to extend the length of time that it takes to cast spells, just arbitrarily extend the casting time. GURPS Thaumatology has lots of suggestions and advice for altering the parameters of spells - if you don't have it, I suggest you pick it up.

Re: Question re: Ritual Magic
 

Not unique items, but they would have to sanctified, which would mean a ritual, probably at least a couple hours long, and should be hand-made. I mist not have read the bit about the Gadgets not being items for sale

Yeah, this is one of those cases where it's hard to decide which to use. I think I'm going to go with a 10x casting time, like (IIRC) in Roma Arcana, rather than the Prep Time limitation (I like this quite a bit, but I don't think that every spell needs to have the same length of prep time), and add the Accessibility: requires Focus to PI. Since the character needs a different focus for each college, but can make new foci as needed, losing one limits what colleges the character can use, but doesn't keep her from casting spells altogether. I'm thinking -10%.

Re: Question re: Ritual Magic
 

People tend not to. :-) It's one of those persistent misconceptions people have about GURPS 4e, so I try to correct it when I run across it. Hope I didn't come off as hostile or anything.

That sounds reasonable. Having to carry around a whole bunch of different items is inconvenient enough that -10% is justified.