Leareth scribbles some notes, snatches the tape and rips out four notebook-pages and tapes them into a bigger rectangle (they have a convenient perforated line for just that purpose), draws a diagram, turns it sideways, frowns at it...

"I do not comprehend your magic at all," he admits finally. "I am baffled by what definition of 'spell' would allow a single such entity to accomplish all of those effects." He runs a fingertip down a line on his diagram. "Your demon calls this a single spell, but given the differing incantations, one could instead classify it as several spells that share a gesture. Most of your spells have a single incantation and a unique gesture, no? So this distinction does not–"

He stops, lifts a hand. "Pause. I wish to make a note of something unrelated." Language is on his mind again, which is probably why he remembered.

"It does not seem like an accident that I arrived here able to understand you," he says. "Meaning, perhaps it is by the will of some entity. In my world, if one has the Gift of Thoughtsensing or Mindspeech, it is possible to instantly acquire a language from another strong Mindspeaker who is fluent in it, via a technique of deep mental rapport and sharing of memory; this could be a related phenomenon." Though different in that he doesn't remember it happening, and also didn't arrive here with a splitting headache. "We ought also wonder if it is related to why, when my Gate-experiment went awry, I landed here in particular. That part could conceivably be coincidence; however, I am suspicious."

He shakes his head. "I am not sure where to go with this question. Mainly, I wish for you to keep in mind that, if some being caused this to happen, we do not know what their goals are. Perhaps a powerful being in your world, angelic or demonic, wishes to see God defeated. I suppose it is even possible that your God is playing games with us. I cannot think of a way to test it now, so all I can suggest is that we maintain vigilance." 

"Yeah, that's--a thing. I don't know what the motive would be but it sounds plausible. I'll keep an eye out for any more . . . purposeful-seeming coincidences."

"Calling prestidigitation several spells that share a gesture might be more accurate, yeah. One of my friends also has spells, and when we try to use each other's gestures nothing happens, but when we try our own gestures and each other's incantations it gets weird results. Partial effects, or overpowered effects, or the spell works normally but something else random happens at the same time."

Leareth is confused, and very intrigued.

"Are there spells that you shared from the beginning?" he asks. "This spell you call 'Prestidigitation', for example, or take any other example – did the demon teach it only to you, or to your friend also? If there are cases of the latter, do the shared spells already have the same incantation?"

The incantations are meaningful – they're in a language that the mysterious force of translation makes comprehensible to him – but the gestures aren't. He knows there are languages of hand-sign, with meaningful vocabulary and syntax; this seems like evidence that the gestures aren't that. Which makes it natural to assume that they shape the function of the spell, and the gestures serve some other purpose – what? 

"Is it necessary that you know the purpose of a spell when casting it?" he asks. "I assume you have tried having your friend teach you one of their incantations without explaining what it does." 

"We have a couple of the same incantations but different gestures for them. We haven't gotten any of each other's spells to work correctly, but they fail almost the same way whether or not we know what they're supposed to be doing. Except for the things you need to mentally specify it fills in something random."

"Rather than failing entirely? Fascinating." Leareth frowns at him; he's going to ask about bringing in Bruce's friends at some point, but he wants to try the experiments that only require a Bruce first. "What happens if you cast one of your own spells and use the wrong pair for gesture and incantation?" 

"Similar range of things to what happens if you use someone else's incantation--underpowered or overpowered or side effects. Also, if you want to see any examples of the latter, we'll want to go to the basement--sometimes the side effects are fire."

"Hmm." Leareth thinks it over for a moment, glancing over his notes. "I would like to see that – it may be informative to observe with mage-sight. Should I conceal myself with an illusion again in case anybody sees us going downstairs?" 

"Probably a good idea, yeah. Unless it's expensive enough that I should scout and tell you when the coast is clear instead."

"It is costly in terms of concentration – I will not be able to manage any complex thinking on the way – but not especially in power." Leareth isn't trying that hard to save every scrap of mage-energy he can, at this point; his reserves can replenish to keep up with regular use of minor magic, and anything major needs a different solution anyway. 

He stands up, closes his eyes, focuses. A moment later, the bed and bedroom wall behind him are perfectly visible, with no sign except for a very faint shimmer when he moves. "Ready." 

Bruce stares curiously at the shimmer for a moment, then leads the way down two flights of stairs to an unfinished basement, making sure to leave doors wide open behind him and doubling back to shut the basement door after Leareth is definitely through it.

And then Leareth is visible again and unfolding his makeshift note-paper. "I am ready to observe." 

"Okay, I'm going to do one that comes out overpowered first and then one that does random stuff. This first one is going to make an excessively bright light."

Bruce attempts to cast Silent Image with the somatic component of Darkvision. The resulting silent image of a green cube is almost too bright to look at.

The corresponding mysterious-language phrase is about what one would expect. Leareth raises a partially-opaque shield to mute the light. (It doesn't block his mage-sight).

"Interesting," he notes. "As before, I can see the energy flow, very briefly; it is more than Prestidigitation used. I cannot, of course, tell whether it is more than this spell would usually require, without also watching you cast the standard version. What is the spell to which the gesture belongs?" He's trying to sort out how power requirements correlate to effect, whether it's the intuitive way he would expect for his own world or something different. 

"The gesture is from Darkvision, which lets me see clearly in dim light and as well in pitch darkness as I can see at night normally. The game the spells are based on says Darkvision is a more powerful spell than Silent Image, but I don't know how accurate the game is or how much Zygynzaxx is deliberately imitating it."

Leareth's mind races. "That is – I will not conclude it would be impossible in my world, but it would certainly be a highly complex spell. Though I think the difficulty would lie in technique and not power; illusions have this property, they require very fine control and focus, and thus advanced training, but the energy needed is minimal. That is why I am not very limited in their use currently."

Pause to make a note. Leareth frowns. "You have not mentioned finding some spells either more mentally arduous or more physically tiring than others. If that is true, there is a large difference between your magic and mine. It seems you are not holding the entirety of the spell yourself? If there is additional complexity in the Darkvision spell versus Silent Image, it is not you who is managing that; it happens elsewhere, hidden." Presumably in a place where Leareth can't see it, although he should observe more castings to compare. "Perhaps by the work of your demon? Or by some mechanism that they built. Tell me more about this game?" 

"Some spells involve holding a mental image, or a mental specification of the effect I want, but they aren't any more tiring than if I concentrated on the thing without casting the spell, and they don't take anything out of my physically. There's definitely something managing some of the complexity behind the scenes, because the illusions I can do are way more realistic than anything I could have painted. The game is . . . well, first of all it definitely doesn't correspond perfectly to reality, because it's got all sorts of rules about how many times you can use which spells per day and I can just cast any of them whenever. But the general idea is that you get a bunch of people to all pretend to be characters in an imaginary world, generally either people with magic powers or people who are really good at fighting, and make up stories about your characters exploring mysterious ruins and fighting monsters and saving the town and stuff. And there are a bunch of complicated rules for what you can have your character do and how to tell whether they did it successfully or not. Like, if you shoot an arrow at someone you roll dice and do some math to decide if it hit."

"Interesting. It bears some resemblance to games I have seen used for military training, but...well, adapted to focus on enjoyment rather than education, I suppose. The correspondence is interesting. Do you think that your demon invented the game? I suppose it would also explain it if another warlock in the past made a game to imitate the magic they had learned." More notes. "In any case, I would like to see a spell with random side effects, next." 

"Demons teaching humans magic has been a thing for a lot longer than the game has, but it could go either way. It probably wasn't Zygynzaxx in particular, because there are a lot of demons and a lot of DnD players, but maybe. He's pretty secretive. You might be better than me at getting him to tell you stuff."

"Spells with random side effects . . . I think I'll go with Mage Hand and the gestures from Detect Magic. That tends to be pretty mild." He does some gestures, says "Create a spectral hand that obeys my will," and the spectral hand appears. It's made of a concentrated and directed blob of ambient magic. Some more ambient magic appears from the same mysterious source, and lacking anything to do with itself it attempts to turn Bruce's hair bright green.

Oh. 

Leareth reaches out with mental hands and snatches the wandering magic, drawing it into his reserves. It...doesn't quite feel like taking in node-energy, but it's not like blood magic either. Maybe somewhere in between.

He closes his eyes for a moment, just enjoying the feeling of power. 

"I think that I took care of the side effects," he says a moment later. "Does it have the same effect every time?" 

Bruce's hair remains un-green! He picks up the notebook in the spectral hand and turns it around. "I think you did! They're different every time but they're usually super obvious. Setting fires, turning things colors, one time I tried prestidigitation with the gesture from  Detect Thoughts and it spontaneously appeared about half a gallon of water. What did you do to fix it?"

"I stole it!" Leareth smiles, briefly, but more broadly than usual. "To be precise, I took it into my reserves, as I would with ambient energy in my world. I think that this solves several of our problems." A pause. "I am very curious about the water. Is there a different spell that creates or transports in water?" 

He watches the spectral hand intently for a few moments. "May I try something? Your hand also appears to be made out of mage-energies. If I am able to use that, and casting the spell costs you nothing, this could solve my issue with replenishing power, at least for minor to moderate-sized casting." 

"There is a spell that creates water, yeah. One sec--" He casts Detect Magic again and then says, "Go ahead and try the thing you're thinking of."

Leareth, concentrating, Reaches in and tugs at the tightly-woven energy, unraveling it and then, before it can dissipate, drawing it in as well. 

The hand vanishes.

It's somewhat more energy than the random excess he had time to absorb before. Leareth almost grins. "Excellent. About ten more of those and I could most likely manage a Gate." 

"Awesome! And I can just spam that all day if you like--with the right gesture this time."

"This is excellent progress." Leareth rolls his neck, shakes out his hands. "I do not actually need to Gate now, however, so perhaps I might observe more of your magic. You could observe more of mine as well with your spell for it, now that I am not limited to very minor workings."