The air is warm, humid and unpleasantly smoky. The sound of a waterfall can be heard nearby. She is in an alley between two tall, ornate stone buildings, and there is a lot more magic around than she is used to, none of it of a familiar type. Among the unfamiliar pieces of magic is a connection binding her to the only other person present in the alley; a man dressed all in blue, his face shaded by a cloak, who in addition to the magic which binds her to him has a second and equally unfamiliar sort of magic in a greater quantity.

He says something in an unfamiliar language and an irritated-sounding tone of voice. The magical connection tells her that it means "You aren't a geologist, are you?".

Wow.

This is so—so much magic—so much all of it what is it she's never seen so much and so different so nothing like anything—

What's this bit of magic connecting her to him? What's this magic surrounding him? ...what's this magic moving in his head—

—it's responding to her thoughts—

—he's reading her mind—

—no no no no nope nuh uh no reading of minds at all no sir her mind is completely opaque to anyone that is not her it is impossible to find her or anything about her without her explicit direct permission (in the form of a specific mental action embedded into the spell) this will last the next hour or so it'll work in such-and-such way done.

The link between Kaede and the telepath, which remains in place, tells her that the next thing he says means "stop that!", and that his not being able to sense her thoughts anymore is annoying and slightly scary.

"Um no thank you I'm happy with my brain staying mine."

The telepath takes a few steps back, closes his arms around himself, and is quiet for a few seconds. Then:

"You can see magic."

"...you caught that, did you."

"Yes. What else can you do?"

"I'm kinda still thrown by the mindreading."

"I'm a natural telepath. I'm really not used to interacting with people without knowing their thoughts, especially people as utterly unknown to me as you are. Not being able to see through your shield is more disconcerting than not being able to see would be. And I don't really see different minds as distinct from each other the way most people do; I'm not convinced you have very much more right to know about a thought than I do just because it happened in your head."

"Oh that's bullpoop, of course you do. Or are you saying I'm allowed to develop a mind-reading spell myself and see what's going on in that noggin' of yours?" she asks. Never mind that that's as far as anyone knows impossible.

He pauses for a bit to think, and leans against a wall.

"I suppose I would prefer you not to do that. And perhaps more to the point there are things I've forgotten so as to make sure other mind-readers wouldn't find them.

Although I suspect I did that because I distrusted those mind-readers' motives rather than out of mere desire for privacy. And I would probably mind you reading my mind less if I trusted you more.

In any case, I'm still not going to give up my telepathy for the sake of peoples' privacy. It would feel like giving up too much of who I am, and a huge part of how I live, and an incredibly useful tool besides. And I don't think I could stand not knowing so much of what was happening around me."

"I didn't say you ought to. Heavy conscience?"

She examines him with her other sense. She thinks if she spent long enough around him she could, in fact, design a spell to render his telepathy temporarily useless. And it's not unthinkable that she could do something permanent... But she doesn't know enough about the situation.

"Tit for tat, you tell me stuff and I tell you stuff, how's that sound?"

"Certainly. I am Jace Beleren, a mind mage and planeswalker. This is the city-plane of Ravnica. I was attempting to summon a Dominarian geologist, but someone over that way" (he indicates a direction) "cast a spell that made mine malfunction. Who are you, what can you do, and what do you want?"

"I'm Kaede, I can do metamagic, I want to figure out what's going on in more detail. I'm in another universe?"

"Yes. This is Ravnica, a world covered entirely by city. One-thousand-and-twenty-three years ago, ten organizations known as the Guilds agreed to share power over Ravnica. They cast a powerful spell called the Guildpact to bind the organizations to their parts of the agreement and bind those of us who were not members of a Guild to nonetheless be subservient to them. Twenty-five years ago, the magical part of the Guildpact finally ceased to function. Since then there have been rebellions against the guilds and wars between them, and the guilds have finally begun to change and adapt rather than stagnating in the complacency of unchallengeable supremacy. But for the most part, the guilds still rule the world and fulfill their ancient functions in it.

One of the Guilds is the Izzet Leage, an organization of engineers, technicians and physicists of which the dragon Niv Mizzet is founder and permanent head. They maintain, or used to maintain, much of the city's infrastructure. Since the Guildpact expired, however, It has increasingly seemed as though Mizzet is becoming less concerned with securing the guild's position or maintaining vital infrastructure than with pursuing some grand secret project. So much so that he has redirected much of the guild's resources towards mysterious ends while dams burst and streets flood. So I've been trying to find out what that project could be.

The project seems to involve, among other things, mapping Ravnica's leylines and streets and trying to find some grand secret structure built into both. I thought a leyline geologist who wasn't from Ravnica might be able to provide a useful perspective. But when I tried to summon one, someone else nearby cast a spell to make spells go wrong, and as a result my spell apparently summoned a metamancer instead."

"Multiple universes are a normal feature? What are leylines and what's a leyline geologist? How long is a year here? How does your magic work?"

"The ability to bridge universes naturally is extraordinarily rare, and the technology to do it with artifacts is rarer. Your world would not be the only one to think itsself alone. It must, however, be extraordinary in some other regards, considering that you carry a type of mana I've never seen before while being unfamiliar with the color you yourself are aligned with.

In many worlds, including Ravnica and Dominaria, most of the world's mana naturally flows into and along certain channels in the ground, which we call leylines. A leyline geologist studies the ways in which leylines and the physical structures of the earth interact with each other, which helps those who cannot see them to nonetheless find and tap them. A year here lasts thee hundred and seventy days.

As for how my magic works, I don't know how much you're already familiar with. Apparently your world has a type of mana I've never seen before, but does it also have regular mana? Does it have black, red, green, and white mana? Do you draw mana from the land and use it to cast spells?"

"No mana from land, not as far as I know. Some people, about one in two thousand, are born magic and generate mana themselves and we have little reason to believe there are any other natural sources of it."

"In most worlds, everything has mana in it, but especially living things and the land. Most mana has a colour. This is blue mana, which is the mana of water and of things which live in water; the mana here is colored by the Dnuul River."

He gestures towards the sound of running water.

"Each color of mana resonates with particular ways of thinking and acting. I am aligned with blue mana because I yearn to understand things and act on that desire, because I think before I act and act on those thoughts, because I try not to allow emotion cloud those thoughts, because I prefer progress to blind traditionalism, and various other reasons along that vein. You are also aligned with blue mana."

"You said there are just five? That seems pretty limited if it's about personality."

"There's a lot of variation within each colour- Methodical thinking can be done according to different methods and with different focuses, for example, and different blue-aligned people have different ideas of progress or ways of dealing with uncertainty. And most people aren't as strongly aligned with a single colour as I am. Blue is the colour of curiosity, methodicality, forethought, logic, and desire for progress but many blue-aligned people only have some of those traits."

"Huh. Am I just blue? What are the other colours?"

"I didn't notice any other colours, but that doesn't mean they aren't there. I didn't get a good look at your mind, and magical sense isn't precise enough to- oh."

"I can have a look with my own magical sense, I guess? I'm not sure how that'd work, though, I've only ever seen blue mana and my magic sense isn't super good at identifying new things very quickly. It'd help if you could point at a thing with more than one colour of mana?"

"Most of the magic in this area is blue like the local mana. But there is some magic of other colours around. I can't tell exactly where they are from here, but we can probably see some from High-Water Street and if not we can go to the Izzet Guildgate."

He heads down the alley towards the sound of running water.

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?"