The Worlds of Katherine Kurtz

Nezz, I agree with you that the key to completing any spell is the understanding of the science and physiology that needs to go into the spell. If you know about all the different pheromones and bodily functions that cause scents, then I think you can replicate it in the Shapechange spell. But if all the caster knows about is the visual differences and the sound differences, would that caster even think to duplicate the smell differences. Unless it was something obvious to our own noses,  like when someone eats a lot of garlic in their diet. Then you would think to duplicate that smell.  But that is only one of many body smells that each of us actually produce. So I say it is all about the spell caster's perception of what he is duplicating when he casts the spell. Therefor, in most cases, he would not fool the dog. Many a pampered pet would find themselves rehomed. Sadly.

Oh Dear!  That is not how I expected Edwin and Aidan to be received. I hold out hope for better understanding.  Revanne... Do tell, what is next?

My thought is that the Deryni Shapechange spell of the Middle Ages/Renaissance Gwynedd—whether illusion or physical—was highly unlikely to fool a dog's nose. Because even though they know that dog's sense of smell is more sensitive than a human's—or even a sensory-enhanced Deryni—I don't think they can fully grasp the sensitivity of a creature with fifty times as many olfactory receptors than we have, along with a brain forty times more powerful than a human's in breaking down scents.

A spell caster (or spell creator) can say "Those dogs can follow a buck's trail using their noses, I'll make sure to hide my normal scent to smell like the new person's scent," but I really don't think they understand exactly what that means. "Hide my scent," to a human, might mean "cover up the scent with perfume or musk," but this really means nothing to a dog who can smell cancer on a person who has been declared cancer-free, or a drug-sniffing dog who can find grams of cocaine in pounds and pounds of coffee.

Dog thoughts: "How quaint, the person thinks he can disguise himself by hiding his eyes behind two fingers."

About 7-9 centuries after Kelson, I think Deryni spell-technicians might create a new spell that has a chance of fooling dogs, once their scientists start to understand dog brains and noses better.

Quote from: DoctorM on July 10, 2025, 06:41:28 PMI keep thinking...does shape-shifting change the physical shape, or just what others see? What sort of shadow does one cast? Can dogs and horses be fooled by shape-shifters? What happens if, say, someone like Christian in my stories-- 5'9, with an archer's build --tries to shape-shift into Alaric Morgan, who's 6'1 and built on a very different frame? What would others see?

It says this in Deryni Magic:

QuoteIt must have been more than mere
illusion, projected on the minds of those witnessing it, for Joram and Rhys saw it, too,
and would have detected a psychic manipulation – as Cinhil himself might have done.
Real change does occur, then. As to how much change, we may, perhaps, gain
some insight by recalling that when Camber needed stand-ins for Rhys and Joram he
chose servants close to their size and body types before working his shape-changing
magic, just as Eidiard was chosen as the model for Davin's shape-change, specifically
because of a general resemblance.

----

All of this suggests that a major limitation to shape-changing is that of body mass
and basic skeletal size. Placing the shape of a diminutive squire on a hulking warrior
probably would not be possible. Nor would a blacksmith make a likely model for a slight
and sedentary clerk. Superficial changes of eye color and hair color, type, and location
obviously are possible, as is some fairly drastic rearrangement of body mass, as in
remolding facial bones, but adding or subtracting body mass is not. (Shape-changing,
alas, is not a Deryni substitute for dieting.) Nor can Tavis simply conjure himself a new
hand when none is there – though he might be able to maintain the illusion of a hand, at
least for some observers and for a short time.

---

The other major limitation of the shape-changing spell, besides conservation of
mass, is that the energy to maintain the spell comes from the subject. Hence, Camber has
his human servants sleep a great deal of the time while they are shape-changed, to
husband their energy. And of course, the death of the subject terminates the spell.

---

Another shape can be placed upon a dead body, of course, as Camber placed his
own upon the dead Alister and Charissa placed a stranger's face on the dead Brion
(adding a further spell to bind a part of the king's soul), but this involves a slightly
different application of the procedure, with input of energy from the operator to maintain
it. Accordingly, such shape-changes on the dead are not intended to last indefinitely.
Camber and Joram are well aware that the Camber-shape on the real Mister Cullen will
have slipped by the time the bishops are agitating to inspect the body, and Charissa would
not have intended her shapechange on Brion to last beyond the coronation, when her
death or Kelson's would render the matter academic.

And gives a number of examples of shape changing. But no where does it talk about how animals perceive it.

I keep thinking...does shape-shifting change the physical shape, or just what others see? What sort of shadow does one cast? Can dogs and horses be fooled by shape-shifters? What happens if, say, someone like Christian in my stories-- 5'9, with an archer's build --tries to shape-shift into Alaric Morgan, who's 6'1 and built on a very different frame? What would others see?

Quote from: Bynw on July 10, 2025, 02:35:06 PMFor another example. I don't recall the names as I type. But the Camberian Council takes a page or squire for I believe Rhys-Michael when he is King and replaces this squire with Camber's grandson. Of course initially his is Blocked and shape changed into the form of the kidnapped page/squire.

So the human boy is already known to the royal household and his own family. Are there dogs that already know and like the boy?

Then he is kidnapped and replaced by a Blocked Deryni under a shape change. How do those dogs react? The Blocked Deryni can't use his powers until later on when he's more established and is unblocked.

It's just a fascinating concept on what Shape Change really does or doesn't do ...
 

For another example. I don't recall the names as I type. But the Camberian Council takes a page or squire for I believe Rhys-Michael when he is King and replaces this squire with Camber's grandson. Of course initially his is Blocked and shape changed into the form of the kidnapped page/squire.

So the human boy is already known to the royal household and his own family. Are there dogs that already know and like the boy?

Then he is kidnapped and replaced by a Blocked Deryni under a shape change. How do those dogs react? The Blocked Deryni can't use his powers until later on when he's more established and is unblocked.

It's just a fascinating concept on what Shape Change really does or doesn't do ...
 

I'm not sure that Stefan/Rhydon would be the best example to use in this case, since Stefan was Deryni (otherwise he could not have served on the Camberian Council), so he would easily be able to use his Deryni gifts to calm any canine animosity towards a stranger. And of course, once the dogs were used to the newcomer's smell, no matter what he looked like, he would no longer be a stranger to them, so they wouldn't feel any need to bark at him after the first encounter or two.

(Re: your dogs barking at strangers even if they can't smell them, it's possible that they can smell them, even when just seeing them through a window and from a distance. A dog's sense of smell is much keener than ours. Though I'm not sure if barking would be the best indicator of non-recognition anyway. Some of the dogs I grew up with would bark if someone arrived at the door even if that person was well known to them and had been for years. Sometimes a bark just means "Hi! I'm excited to see you! Hey, there's someone at the door! Maybe he has food!"  )

A topic came up in our game chat and I think it deserves a wider range of community involvement and thought. So the question concerns Shape Changing.

Deryni Magic clearly tells us that Shape Changing is both a combination of illusion and physical changes.

The subject must be roughly the same height and build in order to change into someone known. You cannot shape change a tall man into a dwarf. And there is no canon reference of any Deryni using Shape Change to take the shape of an animal or object.

These are the known limitations in the use of this fantastic power.

We can deduce that it changes the voice of the user as well. Otherwise everyone would have noticed that Alister sounds exactly like Camber. Or that Brother John sounded exactly like Evaine.

The question was raised, what about dogs? Dogs and other animals recognize people as friend or foe based on smell. (Some like crows and some insects due use sight to recognize others so they could be fooled.) But could a dog be fooled?

We have nothing in canon that states one way or the other. On this question. Now was it left out because dogs too are fooled or was it left out because the author didn't want to bother with it.

"Historically," we know that the time period presented across the novels did have a lot of dogs in use. Humans and Deryni kept dogs for hunting and guarding their homes. My dogs bark like crazy when they encounter someone that is not known to them. Even if they can't smell them.

We know that a Deryni wouldn't have any problem dealing with an animal that smells them as their true-self even though they look like someone else. A little rapport and the dogs will be eating out of your hand.

But we know that there have been cases when a Deryni has placed a Shape Change over someone else. A human or a blocked Deryni. Neither of these would be able to easily convince the dog.

Let's take for example Stefan Coram. He chanced on the opportunity to take the memories and shape of Rhydon of Eastmarch. And lived as him for many years. But when he first took the man's shape. He would have to go "home" to Eastmarch.

Did the Eastmarch dogs react to him as they would to their master Rhydon? Or did the smell an unfamiliar person and reacted negatively to him? Likewise, the same question arises when Stefan/Rhydon goes to Torenth and Wencit. Wencit's dogs may know the scent of Rhydon but does Stefan smell like Stefan or does the magic make him smell like Rhydon or nothing at all?

These and similar questions popped up the other day in chat and are now presented to the full community to discuss.

There is one .... at https://rhemuthcastle.com/index.php/board,196.0.html