Is there intended to be any kind of check, besides spell difficulty and vis cost, on the possible improvement to Characteristics from Creo Corpus or Creo Mentem, or can I freely get all Characteristics at +5 if I have the queens of vis (or Holy/Leper/Hyperborean Magic) it would require?
Freely to +5, if you can handle all those spells. Some SG's prefer to limit them to lower values. I've seen +3 as a limit, too. Vis limits or Warping tend to handle a lot of it, though. Even if you use T: Circle to save Vis, there is noticeable Warping if you do this a lot.
Okay, so if I'm SGing for a Holy Creo specialist (and Holy or Leper magi specializing in Creo is going to be at least as common as Flambeau specializing in Ignem) I should probably have God keep an eye on this kind of self-improvement, even if it's highly thematic for a Holy Magus to do something like that.
Why? It's just characteristics.
Depends on the characteristics. For a magus, Communication +5 is a very good way to increase your Hermetic prestige in a hurry, and Stamina is a boost to all Spontaneous casting totals. Intelligence is, at the level where this can be done, less useful (but it's very nommy for your apprentice), and Strength +5 is only useful to a specific breed of Flambeau magus (though it's highly useful to that kind of Flambeau).
Of course, there's definitely a degree of "if you have the stats to do this, you deserve to be able to do it" there.
Just looking at R: Touch, T: Individual at the moment for simplicity:
If you want to go all the way to +5, you'll spend a few extra Vis to have only one spell or end up developing multiple spells. Most likely your first Characteristic will get two spells to pick up a similar-spell bonus for the +5 one. After that you can use the other +5's for similarity. Still, you're looking at four level-60 spells for CrMe (and another four for CrCo). But a lab total of 120 is needed to do this in a single season. Sure, the +12 for similar spells helps a lot, but that still only drops the lab total to 108 (or 78 for two seasons). Holy Magi would find it harder to get lab assistants who know Holy Magic, so there goes that bonus. Let's say the magus picks up 20 from the lab/aura, now we're at 88 or 58. Intelligence and Holy Magic will drop that some, let's say 80 or 50 now. With the difficulty of advancing as a Holy Magus, picking up the Arts to get a total of 50 is tough, while 80 is really hard. Even a focus, that's a fair amount. So, two seasons for the later three spells and at least three seasons for the first make a total of 9 seasons for those four rituals. Then, knowing you may well botch one after lots of attempts, you might want to master them. That's another few seasons. That's a lot of expenditure and focus not to earn the +5s even without the Vis, isn't it?
The primary check on these, as callen hints at, is not having the lab texts floating about the Order. Houses of Hermes: True Lineages makes something of a case that these are a House Mercere (Cult of Heroes) thing. Of course, anyone can invent these from first principles of Magic Theory if their lab total is high enough, but callen shows how difficult it is when a lab text isn't available. I think they exist, certainly but the trick is finding them, and keeping them secret as part of a Mystery Cult, even. You can make the case that these have been invented by several magi not of House Mercere, even House Bonisagus and there are copies in Durenmar. And that's certainly possible, but it's not easy to get anything out of Durenmar as far as my reading goes, certainly requires a sacrifice of time and/or vis.
An additional check is on individuals who have Poor Characteristic. These spells that raise characteristics shouldn't be effective on them, as it's part of their Essential Nature (page 80, Ars Magica 5th Edition).
There is something of a gray area regarding risk of botch and spell mastery with rituals, it came up in a discussion a while back, which was precipitated by this very issue (raising characteristics via rituals). The RAW is remarkably ambiguous, murky and even contradictory in places, but my sense is that rituals are always meant to be stressful situations and spell mastery doesn't negate all botch dice, merely the number of botch dice equal to the mastery score. For the final rituals to get to +5, level 55/60 rituals (55 if developed at R:Personal), you are looking at a lot of botch dice, starting at 12 or 13 plus others for conditions and then reducing them for golden cord, mastery and rituals.
But all in all, you're looking at a very specific kind of magus to build these, something I don't see as fitting into the Holy Magus mold.
The twelve or thirteen botch dice and matching 11 or twelve pawns of vis are the counter.
I think that if you take the amount of time, vis and effort required to raise a stat a few points and put a comparable quantity of resources into crafting a nifty enchanted device, improving your familiar, or initiating a virtue you'd frequently be somewhat more powerful.
I concur, Erik. Of the characters I am playing and have played that are/were capable of getting to these spells easily are/were motivated by vanity, for the most part.
Tytalus weather maga who might push for the +5 stamina ritual(s) at some point when she's pretty much exhausted all other avenues for improving penetration on Incantation of Lightning. She's kind of obsessed with penetration. She's got a talisman, she can get to books on Penetration, she has mastery of the spell and penetration. She might even pursue original research for Aristotlean Magic Theory so she can add Artes Liberales to her casting score. After all that's done, then it will be the rituals.
A Tremere with poor strength x1 was thinking about the ritual that improves his strength, but I'd already talked to the SG that I wanted it to maintain consistency with the Essential Nature prohibition and the result of the ritual spell would be something other than intended.
A Merceris corpus specialist might learn these spells to cast on the Cult of Heroes, but he has to legitimize himself within the eyes of the House before he gets a chance. He is considered illegitimate because his parens falsified his birth records, but in a twist, he really is legitimate as he has a Latent Magical ability that will turn into Mutantem magic at some point, which everyone knows comes from the blood of the Founder.
The one I'm fond of putting an additional check on is the 'circle' variant:
I'm fine with people inventing the circle variant, but casting circles means concentration checks to draw the big circle; irrespective of the spell casting itself. And those concentration checks can absolutely be botched, which results in the spell itself also botching. Super fun when your entire covenant magi population is inside the circle of better communication...
That's why I'm a big fan of the Cautious with Concentration virtue for PC's that are planning on going this route.
It strikes me that the big value of these spells is improving intelligence or communication. Improving communication increases the quality of books you can produce, which basically nothing else can do (yes, there are the options in covenants. But this is on top of that, and those are very limited.) Improving Intelligence gives you the equivalent of at least an increase in Magical Theory (admittedly without the vis limit increase). But by the time a character can cast these spells, he is likely spending several seasons per increase in Magic Theory (and if he raising it as an exposure effect, many seasons).
Increasing Communication really is worth it, and it's also an ability that makes particular sense to raise later rather than earlier.
Also, of course, don't forget Stamina. For a Hermetic magus who wants to actually cast stuff, that's actually the most useful stat around (probably superior to Intelligence, honestly). Though it's probably worth noting that the magus who actually casts the CrCo60 is more of a lab rat than the one who needs the Stamina boost...
And yeah, the Cult of Heroes is for some reason most likely to cast these spells, but that's probably a Mercurian Magic thing. (Note: While it's technically possible to make a Holy Mercurian Magus ex Miscellanea, the proper response to someone trying this is to pick up a sufficiently heavy object - the corebook will do nicely - and beat them over the head with it.)
I did have a character concept for just that, once - however, I quickly realized that it actually wasn't all that great a build. Rather, a Mercurean magi with TRUE FAITH was much more efficient. That requires that you spend 3 points on a major virtue (like you would have to in order to get Holy Magic, anyway), but would allow you to learn the holy powers/methods fairly quickly.
In-game, this would represent a Mercurean magi who had a Road to Damascus moment (or perhaps a summoning gone horribly right), and realized that this whole pagan thing maybe wasn't the best idea in the world. At which point your first story arc is going out and finding a Holy Order of some sort to learn from. And the consequences of leaving the Mercureans, and whatnot. (Probably nothing deadly, of course - but definitely some pretty severe political repercussions - the least of which your mail never being delivered on time.)
Of course, if you're using Mercurian techniques or Mercurian spells, you're not really doing Holy Magic. There are issues for holy magi casting non-Holy Magic spells. I'm sure those would come into play using techniques based on pagan practices.
Per the rules, the Mercurian Magic virtue can be used with Holy Spells, no problem there.
Have you found an explicit statement of that? I ask, because per the rules it says you can get into trouble if you're a Holy Magus using non-Holy Magic stuff in bad ways, and I would say using pagan (explicitly so according to HoH:S) techniques would qualify as bad. Maybe it's just me, but I have trouble seeing someone with True Faith (Christianity) doing pagan rituals and living up to what he/she is supposed to live up to.
In terms closer to our own reality, what if a cardinal were to start leading wiccan rites in the Vatican? What would the opinion of the rest of the Vatican be? And, more importantly, if the Old Testament and New Testament are correct, what would God's opinion of that be?
Now, it isn't explicit that Mercurian magicians are pagan, but it is strongly associated with a pagan background. Certainly if they were a flamen in the Cult of Mercury it would be idolatry to combine Mercurian and Holy Magic. But even the background of Merurian Magic (the virtue) has a strong pagan background, in that they are the descendants of the Roman priest of Mercury. There is nothing mechanical that prevents combining the two, that's right. But if you are limiting Holy Magic on purely mechanical criteria, you're going to find that it quickly makes such a character incredibly powerful.
It's more that there's no rule against it. Also, back up for a second: the theology on pagan-derived magic is much more complicated, in Ars Magica, than you're making it out to be. As the primarily-Roman-derived Order of Hermes has a patron angel and angels who don't mind working with it, magi can have True Faith without being Holy Magi and can even cast spells that are remnants of Mercurian magic (such as Wizard's Communion)...in fact, they can have Mercurian Magic...I'd say that the default assumption is that pagan magic is not sinful, particularly in light of the veneration/worship dichotomy. Whether pagan magical Virtues (Diedne and Mercurian Magic) can be used with Holy Magic is a thornier question; however, the fluff on Holy Magic is a mess.
Like I said, I personally would not allow it in my saga without a Breakthrough to revise Mercurian Magic into a holy format, but I don't think there's a hard rule against it.
Yes, you're right about True Faith. I should have said "Holy Magic (Christianity)" there, especially since that's specifically what I and we are talking about.