I suggest it does not need to "gel", because the previous definition of Muto acts as a superior filter to all successive descriptions. That is, you don't have to repeat "You can't injure or kill with Muto" in every one of the 10 MuFo Guidelines, because that has already been established.
Let's take the reverse proposition- that for some reason a mage wants to have their veins flow with some other liquid- let's say "water", to avoid Requisite problems, and acknowledging that "water" would be no less deadly than "oil" in these terms.
What does it take to make that change?
RAW, Base MuAq 2 (liquid into another natural liquid) or... meh, call it MuCo 3, a "minor ability" plus one magnitude. With the other Form as Requisite, natch. What is the diff between this and the destructive spell? Mere intent?
For that matter, look at MuCo(Aq) 40 Transform to Water - that turns an entire body into liquid- hell, that should kill someone, right?!
The difference, imo, is Perdo, or the lack thereof. And that's supported by the definition of Muto, of the scope of its effects.
I totally agree with this. Blood has an inherent vital and probably supernatural quality of giving and sustaining life; Muto cannot remove this property, only Perdo can. Changing the liquid into a different liquid won't remove this special, unique property.
We have already determined as per the RAW that entire body transformations into inanimate or (in your suggested case) ambulatory but non corporeal forms would not kill. Intent is in fact an important element in spell casting as demonstrated by targetting a specific group within a larger group shows us.
In the MuAq guidelines the notation for poison and damage upon contact is clearly written as valid, so if this breaks with your "ultimate filter" (and it apparently does) then by all means, let there be an errata to remove any such possibility from the guidelines.
The basic Definition of any Form or Technique is the premise upon which all Guidelines are based, but within those guidelines, any specific differences can be specified. For Muto Aquam to create poisons, these are specific variations, and are mentioned as such. But unless and until such a distinction is made, the basic Definitions still apply.
That is, unless otherwise specifically mentioned in Guidelines or other exception, a Muto spell can't do harm or injury to a target. Why else would that clear and simple statement have been made in the basic Definition?
Same reason one finds in the MuAq guideline box specific reference to "cause (light, medium, heavy, fatal) wound" with only a notation demanding Corpus or Animal requisite if targetting internal bodily fluids, not Perdo.
The answer is, simply oversight or inconsistency (either intentional or by reason of the vast amount of material written) which provides an example of the very grey area you yourself mentioned previously.
I again stress my argument is one of viability not permissibility, since you seem to cling to the latter interpretation.
Edit: It would be appropriate to tag an Apprentice's Parma on this one.
There seems to me to be a small discrepancy within the rules here. The Aquam description on page 121 states that Aquam spells "... cannot affect liquids in a body, such as blood, that requires a Corpus spell".
Now if this was the only statement, everything would be fine, since the MuCo guidelines work very differently than the MuAq. However:
the Muto Aquam description on page 123 states that "You cannot transform liquids within someone's body unless the spell is designed that way (and has a Corpus or Animal requisite)".
The only provided spell that affects bodily liquids is Curse of the Desert PeAq25 (Co), and this does not seem to affect the blood of the target in any way despite the fact that it "Removes virtually all fluid from the targets body". The effect (damage and possibly fatal thirst) seems to suggest that only water is removed in some way.
Conclusion: In the world paradigm of Mythic Europe, blood is not a fluid or liquid, it only resembles it strongly. It seems to be essentially tied to Corpus.
Eh... or it could be an oversight on the designers part.
I think the whole changing blood into poison thing should not be mixed in this discussion. That base is completely within game balance and I think it should work as normal:
MuAq(Co) 40!!!
Make targets blood so poisonous it will kill him almost instantly.
Base 10, +2 voice, +1 part, +1 Corpus, +2 for EF 9
And this only kills when he cannot make a Sta stress roll of 9+ (extra magnitudes will increase this)
These poison rules are balanced out IMO.
The blood to oil uses a nasty munchkin concept: using logic to abuse the rules. (I was reminded by a co-lpayer yesterday, that I am without doubt the best rule-abuser in our group) For me, the statement about the inherent ability of blood to provide life not being changed by Muto is totally acceptable to counter these spells.
Other examples: change all the air in a persons mouth into stone. This stone will have the exact shape of his mouth, so he can't spit it out, nor can he breath. Or disable (Rego) the muscles of his lungs -> no breathing. How about changing his neck to air momentarily -> the head falls of, the neck changes back -> broken or chopped of neck.
Many of such ideas have a very low level, and should therefore not work as good as they seem. You can figure out whatever you like, but do something about such spells. Many will simply not work, others will be slow of allow easy escape/low EF's.
If you want to kill someone, muto his armor to be hard and pointy inwards and hit him with a blunt weapon.
Much easier magic-wise and you do not depend on such high level spells that can fatigue you. Besides, the ones dealing the blows are the grogs, so your magus does not go straight to helñl for killing people. Maybe for being an arrogant jerk that thinks he/she can circumbent the 10 commandments, but not for directly breaking them.
I always thought shrinking a (full) helmet so it crushes the head inside would be particularly lethal for a low level spell. Then again, a spike of wood through the chest should be lethal as well (more than +10 damage anyway, which is mitiated by a soak roll).
Instead, give theeffect a damage number. I still don't think using (only) Muto to change blood into is inherently lethal in the paradigm!
Just realized you're pretty right here: Muto gives you properties you couldn't naturally have. So, changing your blood gives you the property to have changed blood. No harm done. Same with poison: You'd have poisonous blood, so any beast biting you'll poison itself. You won't feel any ill effect.
In fact, you could give yourself (or better, your grogs) alien-like acid blood with muto. You wound't suffer, but your opponents would feel it
To hurt with it, you'd need to follow PeCo guidelines.
The proposed spell is highlights several very interesting points. Here’s my opinion for whatever it’s worth.
The Muto Aquam guidelines on page 123 do state that, with the proper requisite, one can affect the bodily fluids of a person or animal. However, in the prologue to the Aquam section (page 121) it states that such a feat would require a Corpus spell. Corpus guidelines do offer “Level 25: Change a person into a solid inanimate object (Terram requisite)â€. If we substitute an Aquam requisite and a Partial target we could generate an effect very similar to what is described above.
The proposed spell would be completely useless without the Corpus requisite. Therefore a +1 or +2 magnitude increase would be required. Also, sunflower oil is a processed plant product necessitating an additional Herbam requisite.
There seems to be some confusion regarding what Muto can and cannot do. The Limit of Essential Nature is the final arbiter however. Therefore, a human afflicted by Circe’s Curse remains a human being (he is still affected by Corpus spells etc), but his body now resembles that of a pig. Thus it may be inferred that any blood thus affected would remain blood, but possess some of the same properties of sunflower oil. Where we get a little fuzzy is page 78 where it states that Muto cannot inflict harm directly (Eg. transforming yourself into water), but can cause harm indirectly (Eg. Fish on land). This is somewhat confusing, but I would probably rule the proposed effect to be direct harm and thus prohibited.
I also question whether the spell is thematically appropriate. The circulation of blood was not discovered until the 1600s. To the medieval mind (and thus in Mythic Europe) blood did not transport nutrients, oxygen and carbon dioxide, therefore any harmful effects would occur indirectly due to the resulting imbalance of bodily humors (chills, coughing etc.) Indeed I would suggest that Form of the (Temprament) Heartbeast works on a similar principle.
PS. I’m sorry if others have already posted any of these points. I wrote this yesterday, but my computer wouldn’t let me post and I didn’t want to retype the whole thing.
Whether or not blood was known to circulate is not relevant - it was known to be "important". However, I (and the rules) maintain that giving someone poisonous blood would make their blood poisonous to any animal that bit them, not (without Perdo) to that person.
Classic.
Of course, to truly abuse the rules, you'd have to convince the SG that you're affecting the whole neck, and not just "part" of it, so don't need extra magnitudes there.
I must agree, by the RAW (I admit I forgot that specific Muto restriction on causing direct harm), the blood to oil spell wouldn't kill or injure the target. It could be used to "reveal" the target as a demon or changeling which results in his execution, imprisonment or banishement. Thus, indirectly harming the target.
Now, it might be ruled that the blood to oil effect could cause a massive imbalance of bodily humors, though this would probably require an extended effect. For me, I'd have to some more research on the Medieval ideas of humors and how they are supoosed to work or wait until Art & Academe arrives and see if that covers things.
So it seems then that the OP's concerns have been accounted for. Logic (within the game setting paradigm) and game balance are preserved.
Leaving off the debate on the necessity of Perdo requisites for a moment, this intriguing Wikipedia article: en.wikipedia.org/wiki/Medieval_medicine does highlight one aspect which I admit must needs be considered when doing anything to the blood whatsoever. That is, to remain in keeping with paradigm, that blood is most properly associated with the element of air, not water so should not involve any sort of Aq (Mu, Pe, etc) aspect but rather Au.
Interesting. Typically messed up, but in a consistently medieval way.
However, with regard to how it might relate to this discussion, note that Galen et al are breaking things down into the Four Elements, not the 10 Hermetic Forms.
HUMOUR...... ORGAN...........NATURE..........ELEMENT
Black bile___ Spleen______ Cold Dry____Earth
Phlegm_____ Lungs______ Cold Wet___ Water
Blood______ Head_______ Warm Wet__ Air
Yellow bile__ Gall Bladder__ Warm Dry___ Fire
So, unless a SG wants to rule that affecting the head requires Aquam as well, and that bile is not a liquid but either Earth or Fire (depending on which colour of bile), I'd suggest not panicking, and sticking to Aquam.
However, also keep in mind that this is the sort of stuff where "alchemy" diverges from chemistry, and how far apart medieval and modern "medicine" actually are. Not that it doesn't work "in paradigm" in this world, but, for color etc, good for any SG/player to know.
Well, I'd say, PeAq could well be used to draw out the humidity from the body, or even destroy some beer that is still sloshing inside. It's just impossible to affect the bodily fluids, such as blood.
Think of a leaf: surely, it would be impossible to snap it to release any liquid, and you'd need to turn it to mush and somehow strain it to transform the juiciness (the aforementioned integral humidity) into the fluidity of some internal matter.
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Thus, indirectly harming the target.