She follows him.

The alley ends at a corner, and around the corner it leads onto a stone walkway overlooking a wide, swift river. Along the sides of the river, and on islands along it, are tall buildings decorated with beautiful and elaborate carvings. From between the buildings flow countless rushing waterfalls. Joining the sides of the river to each other and to the islands are numerous stone bridges. A bright current of mana flows into the river from a waterfall a way upstream and along it out of sight, and faint streams run into and out of it from the streets and from other waterfalls.

Some of the people in the streets do not appear to be human; there are bald blue-skinned people, tiny green people with enormous noses, and a creature with a single enormous eye. Many of them have magical effects on them, of various kinds. A lot more have magic than did in Galatea.

Jace looks around, and points out a winged woman, who he says is flying with black and white magic.

"Oh, okay, so that's what you mean by colour... hmm..." She closes her eyes and focuses. "I got a bit of black, but very little," she says, slowly, "and my type of magic has zero to do with this whole system." She opens her eyes again, nodding.

"That is very strange. I've never heard of a world without at least one colour of mana before.

"In any case; my resonance with blue mana led to my developing a natural blue mana talent, that is my telepathy. Or possibly my natural blue mana talent led to my personality becming blue-aligned, either is possible. My natural telepathy runs on ambient blue mana, but uses very little compared to spellcasting.

"My resonance with blue mana also leads places rich in blue mana, such as the Dnoor River Leyline, to call to me and allows me to bond with them. Once I have bonded with a place, I can draw on and direct a potion of its mana through arcane gestures."

He gestures, and some of the mana currents around them shift, mana accumulating around Jace's hands.

"Can only one person attune to a place?"

"Any number of mages can attune to the same place, although past a point they will start cutting into each others' ability to draw mana and there are laws about land-bonding designed to prevent that. Laws which give guildmages an abundance of mana and the rest of us scraps, naturally."

"How far away from a place can you be before you can't use it anymore?"

"I could call mana from one side of Ravnica to the other so long as I controlled a band across the plane, and as a planeswalker I can also draw mana from beyond the world."

Jace gestures again, and this time mana comes to his hands from somewhere which is not in any spacial direction.

"Land I don't control is another matter. If I were to call mana to myself across more than a few hundred meters of uncontrolled land, I would expect almost all of it to be lost to natural currents or to someone else's. I can mitigate that to an extent by carrying mana on my person, or sending it through creature bonds."

Another gesture sends some of Jace's mana to Kaede through the connection between them.

"But even then I'd expect to lose it within a few hours."

She nods absently but she got thoroughly distracted by the not-a-spacial-direction and is now staring at it intently.

Looking in the not-a-spacial direction is hard. It's definitely different magically from anything in the regular spacial directions, but it's not direction-y to be easy to look at. Jace has what she now knows to be land bonds heading off into it. Additionally, it's filled with some kind of chaotic magical raw material which isn't mana.

"And that's the second ingredient of spellcasting"

It is obvious he is referring to the non-mana stuff she's looking at.

"What is it? And where is it?"

"Directing mana on its own is relatively limited. It can evoke things' existing potential, for example to activate magical talents too powerful to run on ambient mana alone. Or it can exert influences subtle enough to easily pass for luck. But for spellcasting you need aether.

Aether is matter without fully defined form or place, chaotic potential. It naturally occupies a shapeless not-space we call the Blind Eternities- which is what you're looking at. To cast a spell, one must not only shape mana into the correct form but also provide the proper configuration of aether to give it substance. This requires an incantation; for example, to cast a general counterspell I might incant 'He Imonshobi Vume'."

This last phrase is sung.

"Huh. It's magic."

"It does feel as though your metamagic can influence it. It isn't magie as we understand it.

The final component of spellcasting is the template, which is needed to shape the forces involved as precisely as is necessary. In the most basic form of spellcasting, this is knowledge and understanding related to the spell which the caster puts into the spell and which provides the pattern the aether and mana use to shape reality. For example, for the spell which ended up summoning you I used some of my knowledge about Dominarian geologists. This knowledge is either left int the magical construct or consumed. The other way to provide a template is alchemy, in which the template is a physical structure produced outside of the caster's mind through the careful selection, and combination of materials. This allows the alchemist to cast spells without sacrificing parts of themself but is significantly more expensive and difficult; it is not unusual for a recipe to require a signigicant quantity of precious metal heated to immense temperatures or pearls harvested on a specific day several years ago, for example."

"Several years ago?"

"That would be typical. Sometimes an alchemist can develop a recipe that only requires recent harvest dates, or a more complicated spell can only be done with an ingredient from decades ago. Does your type of magic normally use newer materials?"

"My type of magic doesn't need any external materials. It produces magical artefacts but it doesn't need to use them for anything."

"And on that topic- how does your type of magic work. Your mana is different and only comes from people, and I gather that you don't use alchemy. How else is it different?"

"Okay, I'll... explain it from the ground up. A few people, like one percent of the population or so, are born with magic. That means they have roughly the same chance of being one of three types of mages, or an even tinier chance of being the type of mage I am—metamancer. Following so far?"

"Yes."

"You can't natively figure out whether anyone's a mage unless you see them doing magic or they tell you—or you're a metamancer. You can't, in fact, even figure out if you are a mage yourself, normally. The only way to do it is to actually do magic, but there isn't a single way of doing magic that works for everyone, so you just gotta try. Most people spend their childhood and adolescence trying, thinking about it, trying to feel it, or whatever. After their twenties or so people tend to stop trying but figuring out you have magic when you're older than that is not unheard of. If you succeed at doing magic, it's usually in a very uncontrolled fashion, and since you've been building up your mana reserves since you were born, that can be pretty disastrous, depending on which type of mage you are."

"And which types of mage might you be?"

She starts counting off her fingers. "Arcanists, who do magic with symbols; elementalists, who do magic with their bodies; enchanters, who do magic with objects; and metamancers, who do magic with magic itself."

"We have people who do magic with all those things, but they aren't fundamental categories of magic like it sounds like they are for you. And you don't have colored mana, and you don't use aether or spell templates, and the only source of mana you know of it people? This is fascinating. It sounds as though your world's magic is fundamentally and comprehensively different from magic in every other world I know of. Do you have any idea of how it could have come to be that way?"