Quote from: amacris on June 14, 2021, 04:40:41 AM

Quote from: GeekyBugle on June 12, 2021, 12:56:55 PM
You're thinking of a classical D&D fantasy type of game, this isn't going to be that. Think Conspiracy X but only with supernatural enemies. And you're on the team that knows monsters exist and are hunting them.

Which is why I either manage to create a coherent system of White/Gray/Black magic or I make all MU NPCs (With the exception of the Cleric).

It's also a monoteistic world. You have God and against him Demons and Demonspawn. You're on the side of the angels.

It might not be something most find fun or it might be a hit who knows?

I think it's awesome that you're doing this. Objective "God-given" morality is great for gameplay -- it creates interesting mechanics and allows for a certain moral clarity of action that can be really refreshing if you've spent the last 50 sessions in ambiguity. I wrote some rules for ACKS/BX magic that translates the spells into White, Black, Grey with penalties / corruption for mis-using Grey and Black. Hit me up on DM if you want me to send them to you.

Thanks, IMHO I think there's already a lot of that "polyteism" and nothing is evil/good in the market, It still might flop, it might not, who knows?

I've seen some OSR games or supplements breaking down D&D spells into White / Gray / Black. Unsure which one offhand unfortunately, but I remember having some issues with some of the categorization.

Especially because it appears White = Good Magic and Black = Evil Magic which is perfectly fine, but lots of magic spells don't fit easily there and its weirder when the Evil Wizard heals his minions with white magic and the Good Priest drops an evil fireball on the goblin horde.

Perhaps the answer is removing Good & Evil from the White & Black definitions of magic BUT...black magic has tremendous association with evil.

Warhammer went with "all magic is from Chaos", aka if its not blessing from Sigmar (or the neutral gods of the Old World like Morr), then its Chaos tainted.

DCC RPG seems to operate from a similar idea.   

Quote from: Spinachcat on June 23, 2021, 11:56:15 PM
I've seen some OSR games or supplements breaking down D&D spells into White / Gray / Black. Unsure which one offhand unfortunately, but I remember having some issues with some of the categorization.

Especially because it appears White = Good Magic and Black = Evil Magic which is perfectly fine, but lots of magic spells don't fit easily there and its weirder when the Evil Wizard heals his minions with white magic and the Good Priest drops an evil fireball on the goblin horde.

Perhaps the answer is removing Good & Evil from the White & Black definitions of magic BUT...black magic has tremendous association with evil.

Warhammer went with "all magic is from Chaos", aka if its not blessing from Sigmar (or the neutral gods of the Old World like Morr), then its Chaos tainted.

DCC RPG seems to operate from a similar idea.

And what makes you think that my cleric performs magic? Miracles, performed by God by intersecion of the Cleric. So it's not magic, also what makes you think I'm going to give the Cleric the exact same "spells" that the OSR uses?

So one problem solved.

I agree that the evil wizard healing his mininons might sound like something good... Until you realize that to do it he stole the life of innocent people so his minions could keep on serving him in his evil plots.

Type of spell matters, but it also matters intent and means to power the spell. The second and last maybe more than the first.

So it's a bit more complex than it sounds. It's not put all the healing spells in the good side and all the fireballs in the evil side.

Let me take it from a different direction - I think while you don't want Vancian magic, the responses are diving directly into Vancian frameworks. Specifically by saying what kind of magic is Black Magic... the very framing that we seem to be debating is the specific effects.

You might want to consider thematics over effects. For example - Can Black Magic *Heal* where *Heal* is the effect? Can Black Magic *Raise Dead*. Conversely, can White Magic *Heal* and *Raise Dead*? Then we shouldn't be debating the effects, rather the thematics and what Black Magic (and any other school/form) has as a thematic quality.

In this case I'd say Black Magic is inherently "entropic" - therefore it can never create something out nothing. It *always* subtracts. So in this case it can *Heal* - but only by draining something else. It can *Raise Dead* only by killing something else. So it depends on how far you want to extend the metaphysics of it. You might figure out what realms or modes of magic exist to produce what discrete effects.

So if Mental qualities is something you're going to have - perhaps Black Magic only "corrupts" Mental States. Removes senses. etc. But it can't for instance instill positive things - like love. That would be the province of another school (Like Enchantment or something).

OR maybe you can do it with Black Magic but it has to cost something.

Raising Undead is a hallmark of Black Magic but it's not creating something so much as it's instilling entropic energy to animate something already dead. Soul capturing, Possession? I'm tossing stuff out there. Life-force draining and redistribution.

Perhaps direct damage by way of casters using their own life-force?

I kinda feel that the gotcha for Black Magic is there should be a pain-algorithm. So it's nasty in effect, but inefficient in doing pseudo-positive things. So it might drain you of health, but produce +25% more in damage. While "healing" via life-drain is only 50% effective because inherently Black Magic is entropic not regenerative.

Anyhow - that's how I look at it.

Quote from: tenbones on June 24, 2021, 03:12:05 PM
Let me take it from a different direction - I think while you don't want Vancian magic, the responses are diving directly into Vancian frameworks. Specifically by saying what kind of magic is Black Magic... the very framing that we seem to be debating is the specific effects.

You might want to consider thematics over effects. For example - Can Black Magic *Heal* where *Heal* is the effect? Can Black Magic *Raise Dead*. Conversely, can White Magic *Heal* and *Raise Dead*? Then we shouldn't be debating the effects, rather the thematics and what Black Magic (and any other school/form) has as a thematic quality.

In this case I'd say Black Magic is inherently "entropic" - therefore it can never create something out nothing. It *always* subtracts. So in this case it can *Heal* - but only by draining something else. It can *Raise Dead* only by killing something else. So it depends on how far you want to extend the metaphysics of it. You might figure out what realms or modes of magic exist to produce what discrete effects.

So if Mental qualities is something you're going to have - perhaps Black Magic only "corrupts" Mental States. Removes senses. etc. But it can't for instance instill positive things - like love. That would be the province of another school (Like Enchantment or something).

OR maybe you can do it with Black Magic but it has to cost something.

Raising Undead is a hallmark of Black Magic but it's not creating something so much as it's instilling entropic energy to animate something already dead. Soul capturing, Possession? I'm tossing stuff out there. Life-force draining and redistribution.

Perhaps direct damage by way of casters using their own life-force?

I kinda feel that the gotcha for Black Magic is there should be a pain-algorithm. So it's nasty in effect, but inefficient in doing pseudo-positive things. So it might drain you of health, but produce +25% more in damage. While "healing" via life-drain is only 50% effective because inherently Black Magic is entropic not regenerative.

Anyhow - that's how I look at it.

Looks like you understood where I'm coming from and also like you found a workable solution.

But... Wouldn't that make Black magic less powerful than the White kind? Where's the temptation to use it if you can use White magic and it's more effective?

Also what about Gray magic?

I suppose it depends on how you want to break down the "schools".

Black, White and Grey seem overly broad to me, imo. But it depends on what kind of magic you want to emphasize.

Typical magical cosmologies will have Postive (White) Negative (Black), then have the Four Elements in between. Of course there are others that go to the abstract leveraging the Kabbalaistic sorts of systems where you have specific "domains"- Mind, Spirit, Forces, Material etc. And then you specify how White/Grey/Black interact with each and those interactions are modes which produce effects.

Mage conceptually does it in an interesting way with its Spheres. I think their system sucks over all in expressing it.

Talislanta 4e does it pretty well. You have Modes which dictate mechanics, and the Schools have access to specific modes, which are granted bonuses and penalties to those kinds of effects.

Savage Worlds approaches it purely from a game-mechanic perspective by giving your the mechanics of an effect, then your school (Black, White, Gray in his example) apply "Trappings" which directly affect the Effect. Their spells are discrete powers that may/may not exist in the Spell lists of the respective school.

So it means you have to codify what kinds of effects are possible, then denote how each school interacts with those effects. It can be a lot of work but I think it's worthwhile if you put some effort into thinking about what kind of magic you want in your world.

1) Decide what kinds of effects do you want possible? Elemental effects? Abstact effects (Mental, Spacial, Chronological?)
2) Or do you want to do it by category - where broad effects are possible under some kind of taxonomic divisions. Law/Chaos - where between each category you have distinct schools that have effects which differ based on things that create order vs. things that create entropy. You'll have to denote how those distinctions matter in your setting.
3)  Magic the Gathering isn't a decent system to riff off of structurally. Chaos/Power, Life/Nature, Entropy/Death, Mind/Arcane, Order/Purity.  And of course they have a big catch-all neutral for "technology" which is neutral, but has a lot of ties to the abstract Mind/Arcane.  You can easily break these down into setting-specific camps and determine the types of effects you want and apply bonuses and penalities according to the school in question and the order of magic they practice.

Just some food for thought!

As for the temptation to go Black. Well the "traditional" idea is that Black Magic should cost you something yet give you instant results. Or something to that effect. As Yoda says - the Dark Side is the short-cut to power, not wisdom. But again the problem with this model is that it assumes certain undeniable realities of a binary Black/White system in terms of a mortal's interactions. You may not want that.

Me? I like magic being dangerous, but the question we're talking about it whether the mere practice of it is some kind of existential spiritual threat unless <X>. Where <X> is "sanctioned" method to engage with such forces. Sanctioned by who? Gods? The limits of magical ignorance? Physiological/Psychological limits of mere mortals? All of the above?

There's a lot of rabbit-holes you can go down with it. I think it might be better to approach it from a game-mechanic perspective and tweak to the narrative realities, unless you want to really ponder what magic really means in your setting. I go through this shit all the time with my own stuff, heh.

Gray Magic

What does that mean without some kind of moral authority guiding the intent of the forces? One interesting idea that comes from R. Scott Bakker (philosopher and fantasy writer) is that "reality" is comprised of the most powerful being's Subjective Will. So the fantasy setting of his novels - Mages have figured out the secret methods to work magic - which is to rearrange reality, but because their understanding of reality is imperfect, it causes their spirits to slowly decay. The reason for this is that the God's subjective reality - which creates the world, is so vastly powerful, it becomes OBJECTIVE reality to lesser creatures (like mortal men).

Get your head around THAT as a fantasy setting magical cosmology. Then he has Aristotelian (Effect's based) and Platonic (Vancian) magic working side-by-side, as mere descriptors of how mortals are playing with the tools of the Gods and ruining their souls. And only one school in his setting is capable of working magic without scarring their soul, and it's a school that is largely subtle and psychic in nature. And none know why this effect exists or why the respective schools can only work magic in the way they do.

It's pretty fascinating stuff.

He has one over-arching explanation for Magic. It's based on meaning. The larger reality is that the Gods create reality from their own subjective power and construction of their reality which we all live in. Mortals practice magic that describes (or rewrites) their objective reality via three methods relating directly to meaning -

Representational Logic - Sorcery that describes the Effects which are discrete to the capacities of the Sorcerer. Think of it as magical logic problems and utterances combined with thought constructs of insane structure. This literally describes the effect (and is powerful as fuck).

Anagogic Logic - An inprecise method of not fully understanding the forces which describe a specific effect. This would be a Vancian spell. Where the Logos version of Representational Logic would understand the forces of fire, and create specific effects on the fly, the Anagogic sorcerer knows how to cast Otilukes Flaming Sphere - which doesn't understand where the sphere, or the fire comes from, just the specific rotes and actions which allow the spell-effect to take place. They can't pull off the stunts that a Logos-based sorcerer does. Nor do they know how the Logos based sorcerer does that they do.

Impetus Based - The foundation of any effect comes from the psychological impulse to extract meaning from reality. In Bakker's setting - these practitioners cut to the heart of meaning for their effects which do not warp reality as much as reveal or create effects that are subtle and powerful. Less flashy, but ultimately it's working in context with the Subjectivity of Reality as laid down by the Gods. So lots of psychic effects, subtle manipulations, etc.

Quote from: tenbones on June 24, 2021, 05:23:02 PM
I suppose it depends on how you want to break down the "schools".

Black, White and Grey seem overly broad to me, imo. But it depends on what kind of magic you want to emphasize.

Typical magical cosmologies will have Postive (White) Negative (Black), then have the Four Elements in between. Of course there are others that go to the abstract leveraging the Kabbalaistic sorts of systems where you have specific "domains"- Mind, Spirit, Forces, Material etc. And then you specify how White/Grey/Black interact with each and those interactions are modes which produce effects.

Mage conceptually does it in an interesting way with its Spheres. I think their system sucks over all in expressing it.

Talislanta 4e does it pretty well. You have Modes which dictate mechanics, and the Schools have access to specific modes, which are granted bonuses and penalties to those kinds of effects.

Savage Worlds approaches it purely from a game-mechanic perspective by giving your the mechanics of an effect, then your school (Black, White, Gray in his example) apply "Trappings" which directly affect the Effect. Their spells are discrete powers that may/may not exist in the Spell lists of the respective school.

So it means you have to codify what kinds of effects are possible, then denote how each school interacts with those effects. It can be a lot of work but I think it's worthwhile if you put some effort into thinking about what kind of magic you want in your world.

1) Decide what kinds of effects do you want possible? Elemental effects? Abstact effects (Mental, Spacial, Chronological?)
2) Or do you want to do it by category - where broad effects are possible under some kind of taxonomic divisions. Law/Chaos - where between each category you have distinct schools that have effects which differ based on things that create order vs. things that create entropy. You'll have to denote how those distinctions matter in your setting.
3)  Magic the Gathering isn't a decent system to riff off of structurally. Chaos/Power, Life/Nature, Entropy/Death, Mind/Arcane, Order/Purity.  And of course they have a big catch-all neutral for "technology" which is neutral, but has a lot of ties to the abstract Mind/Arcane.  You can easily break these down into setting-specific camps and determine the types of effects you want and apply bonuses and penalities according to the school in question and the order of magic they practice.

Just some food for thought!

As for the temptation to go Black. Well the "traditional" idea is that Black Magic should cost you something yet give you instant results. Or something to that effect. As Yoda says - the Dark Side is the short-cut to power, not wisdom. But again the problem with this model is that it assumes certain undeniable realities of a binary Black/White system in terms of a mortal's interactions. You may not want that.

Me? I like magic being dangerous, but the question we're talking about it whether the mere practice of it is some kind of existential spiritual threat unless <X>. Where <X> is "sanctioned" method to engage with such forces. Sanctioned by who? Gods? The limits of magical ignorance? Physiological/Psychological limits of mere mortals? All of the above?

There's a lot of rabbit-holes you can go down with it. I think it might be better to approach it from a game-mechanic perspective and tweak to the narrative realities, unless you want to really ponder what magic really means in your setting. I go through this shit all the time with my own stuff, heh.

The setting in very few words: Monsters are real, this includes anything not human. God is real (in singular), so is Lucifer and other demons. Clerics don't work magic, they manage to work miracles by interceding so God does X. Black magic is evil (maybe all magic if I can't find a way to work around it)

Now, if I'm to include some magic user as a PC I need to find a way to separate magic not into schools but into types: White, Gray Black, where Black magic comes from Demons or torture and human sacrifice, White magic uses "natural" energies and does not harm except in self defense or protecting the innocent. Gray magic somehow is in the middle of that (I might do away with Gray magic altogether since it's the hardest to get right).

So any person could do Black magic but it leaves a taint, it corrupts your sould making you more likelly to do the bidding of demons. The more you use it the bigger the taint (some spells have a bigger taint perse). To cleanse yourself you have to do X (Pray, penance, a quest,etc) but beyond a certain point you can never fully clean the taint if at all.

White magic on the other hand has no such cost, but it's less fast/powerfull since it has restraints in the means to power it and the uses.

You are playing as monster hunters.

Geeky, it might not hurt for you to dig out the old Dragonlance books and see what the three orders (White, Red, Black) were limited to in terms of spells.  Could be useful.

I believe the Black Robes also advanced faster than their other counterparts.

Quote from: Ghostmaker on June 25, 2021, 10:00:14 AM
Geeky, it might not hurt for you to dig out the old Dragonlance books and see what the three orders (White, Red, Black) were limited to in terms of spells.  Could be useful.

I believe the Black Robes also advanced faster than their other counterparts.

don't have them, and don't have the money to buy them right now. But it's something I will do as soon as I have some extra cash.

I think you're going to need more theology to flesh out your setting, but from what you're saying, I think what you need to do is to define your poles better.

So, in a polar system, white magic is magic that is directly aligned with God and God's will.  This is a bit more complicated than just not using violence in self-defense, since (I assume) the setting includes angels and smiting and so on, but the point is that it is magic that specifically fulfills the will of God directly.

And, accordingly, black magic is magic that specifically thwarts God's will, or aligns the user with Satan.  This is again set directly according to what God wants, just in the opposite direction.

And in this polar structure, grey magic is magic that is not aligned in either direction.  Alchemy, or herbalism, or simple elemental magic that is of the physical world and has no moral dimension, does not lead you directly to demons and Satan, but it does not lead you to God, either, and if you practice it too deeply, you can end up thinking that you have this wonderful structure that can solve all your problems and has no need of God, which is deeply hazardous.

In this setting, most D&D magic is Grey, and the big deciding factor is how you use it.  Disguise magic is morally neutral, in a spherical vacuum.  If you habitually use disguise magic to make yourself look prettier, you might be making yourself prey to the sin of Vanity, which will start tainting your magic disguises.  Conversely, a village wizard using disguise magic to give himself a different appearance every morning when he wakes up to amuse the villagers and reassure them that yes, he is a practicing wizard what does real actual wizard magic and not a charlatan, would be simply Grey, and that wizard using their magic to swap appearances with an injured witch-hunter convalescing nearby, and lead away a pack of blackguards seeking to murder the vulnerable witch-hunter, might be a White usage of normally-Grey magic.

Quote from: robertliguori on June 25, 2021, 11:57:51 AM
I think you're going to need more theology to flesh out your setting, but from what you're saying, I think what you need to do is to define your poles better.

So, in a polar system, white magic is magic that is directly aligned with God and God's will.  This is a bit more complicated than just not using violence in self-defense, since (I assume) the setting includes angels and smiting and so on, but the point is that it is magic that specifically fulfills the will of God directly.

And, accordingly, black magic is magic that specifically thwarts God's will, or aligns the user with Satan.  This is again set directly according to what God wants, just in the opposite direction.

And in this polar structure, grey magic is magic that is not aligned in either direction.  Alchemy, or herbalism, or simple elemental magic that is of the physical world and has no moral dimension, does not lead you directly to demons and Satan, but it does not lead you to God, either, and if you practice it too deeply, you can end up thinking that you have this wonderful structure that can solve all your problems and has no need of God, which is deeply hazardous.

In this setting, most D&D magic is Grey, and the big deciding factor is how you use it.  Disguise magic is morally neutral, in a spherical vacuum.  If you habitually use disguise magic to make yourself look prettier, you might be making yourself prey to the sin of Vanity, which will start tainting your magic disguises.  Conversely, a village wizard using disguise magic to give himself a different appearance every morning when he wakes up to amuse the villagers and reassure them that yes, he is a practicing wizard what does real actual wizard magic and not a charlatan, would be simply Grey, and that wizard using their magic to swap appearances with an injured witch-hunter convalescing nearby, and lead away a pack of blackguards seeking to murder the vulnerable witch-hunter, might be a White usage of normally-Grey magic.

D&D magic is a convoluted mess.

Trust me I'm not fleshing out everything here because it would be a lot to read.

I've already said (probably in the opening post IIRC) that type of spell matters, but how you power the spell matters too and why you're casting the spell matters too.

My not-Cleric doesn't cast spells, he works miracles God willing.

All this is to try and include a MU Class as a PC.

So a few different aspects have been talked about as possible conditions for making magic black. Why not combine these into how you define an individual use of spellcasting? If two or more are "black marks" then the spell use is black, if only one then it's grey, and if none are then it's white.

Aspects:

Source of power: using the alignment of the stars, or the full moon, a piece of wool cloth crafted for a loved one wouldn't be black. But drawing on an infernal deal, or a blood sacrifice would. (A human sacrifice could be 2 black marks automatically.)
If a source of power is black it could increases the potency of the effect by 50%.

Emotional State / Speed of Casting: a calm carefully considered spell, made in a peaceful situation is white -- someone being healed may be in distress, but if conscious are willing to have the mages minstrations. A rushed spell or one made due to a fear or anger (the fear or anger help to quickly cast the spell) is black -- because you haven't carefully considered the outcome, and been confident that you are acting according to God's will.
If emotional state is black you can cast very quickly.

Intent and Immediate Outcome: Is your intent "good" / holy? Is the outcome "good" / holy? If not then it's intent is black.

Spell Effect: some spell effects could always be black. Like creating undead (corruption of the natural order), or destruction, or . . . you've had a lot of suggestions for these.

What's key with this method would be that you define fairly clearly what is black, everything that isn't defined as black is white/neutral. Having a single aspect of the spell usage be black makes the usage grey. While if two or more aspects are black then it is black.

This may be more complicated than you want, but it felt like a useful synthesis of some of the discussion.

I second Mishihari's suggestion of the Lord Darcy books.  Mainly because there is a lot of in depth discussion of not only black/white magic in them, but the two main characters frequently discuss the "why" aspect of it as well.  One of the secondary characters in a longer story is a monster hunter from Mexico!  It often gets into where to draw the lines on "intent".

I may be misremembering, but here are some of the key principles best I can recall:

1. White magic can't directly attack anyone.  What it can do is set up a kind of judo affect where attacking a white magician is a bad idea--the outcome is some mixture of disabling the attacker (e.g. paralysis) or even shielding/reflecting hostile magic on the caster.  Some white magic can make you very confused in a variety of ways. 

2. Thus the primary motivation for black magic is that it lets you act on your (frequently misguided) passions--hate, revenge, lust, jealousy, greed, etc.    It's almost a tautology in how it is comprised, where it is not necessarily clear which way the cause and effect run.  Do you hate someone and then succumb to using black magic because you can't control your hate?  Or do you slip into using black magic (similar to being "curious" about crack cocaine) and then you start expressing your hate with the magic because it is black?  Either?  Because black magic rebounds on the caster, too, AND it is addictive.  Black magic and misguided passion create a negative feedback loop, where one reinforces the other as they spiral out of control.

3. What's the appeal of white magic, then?  It can build things.  It becomes a replacement for science in some cases (e.g. advanced tech in terms of the setting).  It can discover and analyze--including finding black magic. 

4. Charms and enchantments kind of bridge the gap between white and black, with the dividing line between what is already mentioned.  A charm that makes your right arm stronger is probably white, though exactly how you went about it could make certain forms black.  White mages can turn invisible (with difficulty) and levitate (difficult) or fly (really advanced).  Black mages can do those things too. 

5. There are certain things that "magic" can't do, period, white or black.  It can't remove a possessing spirit, for example, which requires a priest performing the appropriate ritual.  There is a kind of "psychic surgery" that is performed by very skilled priests who are also magicians.  In fact, the whole idea of priest versus magician are not opposed but largely orthogonal.  Priests have certain inherent powers (akin to the "miracles" I think you are describing).  Magicians manipulate highly advanced constructs that requires a solid understanding of mathematics, "science", etc.  A "healer" can come from either or both, but the effects are different.  A journeyman magician healer is subordinate to a priest or a senior magician.  They can't heal a patient.  They can bandage, clean, etc., that is make up the conditions to keep infection out if it hasn't already occurred.  Occasionally, a priest shows great aptitude for magic and is advanced on both paths. 

6. A person can leap hard into black magic, and quickly become entrenched.  Or they can edge into it, and be "saved" if caught in time, and they are willing to back out.  The hard drugs metaphor is I think a really good way to visualize it. 

Really, the whole series is a case book study of how to make a world to showcase how white "building" and "knowing things" is very powerful. Whether or not that makes a good basis for a game or not, I'm not sure.

I think nice example is used in Dresden Files urban fantasy - where wizards have code of seven condemned kinds of magic, which are bot capital legal offence, and also soul/mind corrupting ones even when done in good faith and justified reasons.

In DF those are:

1. killing other humans (become grey when you kill supernatural post-humans, or when you cause death indirectly, become ultra black when you rip vital life directly from bodies)
2. transforming humans in other beings (transforming yourself is grey as you kept more control, but still imbalance between mind and body is not healthy)
3. invading minds of others (includes telepathy and so on of most kinds, the more invasive the more black, mind-probing is sort of grey, reason for it is - two minds interacting with each other - which is only way to do psychomancy will invariably influence each other in abberant way)
4. enthralling others (as above, though there are ways to do it without psychomantic effect on yourself, like with truenaming it's still destructive for your thrall, here law forbids even direct enthrallment of spirits for same reason)
5. necromancy of all kinds (including ressurections) - mostly because contact with energies used for it, is corrupting for wizards (and because no one really knows whether ghosts consist real souls within)
6. chronomancy (avoiding paradox - though uncertain whether it cause harm on user, potentially enforced to avoid alternate reality hopping)
7. seeking beyond outer gates (calling demons in limited fashion can be accepted as long as you not bind them by force, but calling monstrosities from Cthulhu land gets your head guillotined faster than you can say Yog-Soggoth)

QuoteSo Frex the Orc is about to kill a child, your only chance to stop him is magic missile, so it is still black magic?

May be. Fabric of reality may be thing precious enough to limits uses even when it costs human lives to do so.

QuoteYou're going to cast a healing spell, but you use human sacrifice to power your magic... Is it white magic? It's altruisticand doesn't inflict harm (the spell doesn't)

Well in vain of classic Catholic way of constituting elements of sin - we have matter of sin, knowledge about sinfulness and freedom of will - as three elements included in building moral weight to judgmenet. If some are lacking there is no mortal sin for instance.
In terms of magic we can take: matter of spell itself (specific pattern of mystical energies that may be in accord or against with natural law), method of spell (how you mantain enough energy to control this pattern), intention of spell (be it wicked or virtuous). If all dots are fine - you get White. Two - you get Grey. One dot or neither - Black.

Now the pattern I think could be nice shown on base of WoD Spheres of Magic. Like in Christian morality you have sort of three levels - Perfect Nature, Fallen Nature, Against Nature.
Comparing it to WOD - Against Nature is like Qlippoth, it's basically high end Chaos Magic breaking utter discord on reality. Life becomes Undeath, Fate is replaced by utter Randomness, continuum itself breaks. Fallen Nature is still wrong, but not trying to distort reality altogether. The intention system could be based on some Virtue/Vice system, when practicing Vices and Virtues may a) influence how Reality shall read magician actions (even sort of despite character self-delusions or how else we call Player's Choices, these days), but also linking how non-magicians can interact with magic - having specific Virtue Vice high can make you vulnerable or invulnerable to specific spells and even specific magicians. And to blood sacrifices I'd add other debaucheries as illicit methods - profanations, sexual debauchery, corruption of just works of other men and so on, sort of in line with Chaos Gods of Warhammer insanities.