Not through the door, no. This person has been around for a while, observing. A young woman, white, with a suit and a hat, long dark hair in an efficient ponytail.

And she decides to approach. "Hello."

She looks up, smiling slightly. Her teeth are the sort of white you only see in faked pictures, her skin smooth and free of the tiny imperfections that betray a life lived.

"Hello," she replies.

The raven (?) on her shoulder cocks his head, numerous red eyes blinking out of sync, and ruffles his feathers, black and iridescent with the colors of the night. "And who might you be?" he croaks, twisting his head back and forth to get a good look at the new woman.

"I'm usually called Contessa. May I sit?"

"Feel free." And she gestures to a seat; her fingers seem a touch too long for a moment. "Please excuse my daemon's manners, he's usually not like this." And she mentally brushes against him over their link; something must have caught his eye. "I'm Navis, my daemon here is Tycho."

(An extradimensional connection? Interesting; Tycho hasn't gotten any detail beyond that, yet, though he might not, with Milliways as it is.)

"Was there something you needed?"

"Yes, but I'm not yet sure if you can help with it. I'm also unfamiliar with daemons."

"That's not unusual, I've found they're relatively uncommon as these things go - daemons are pretty much external souls, that, in the world I'm from, take the shape of animals. In my world, they have abilities that usually complement their humans' - mine's one with what most worlds would call magic. It's incredibly rude to touch someone's daemon without permission, outside of emergencies. Often considered a form of assault."

"As for your problem, I try to help where I can. My primary ability lets me find things; this has come to include paths to complete goals."

"That's interesting. My world has some forms of abilities that others might call magic, but whether it really is magic is debatable. Souls don't obviously exist."

She really wants to ask about the world more, but...

"There was a similar debate in my world. Most people didn't believe in magic in modern times. What is it I can maybe help you with? I can explain my abilities and some past cases more in depth if you'd like, if you're reluctant to share cold."

"I would like that, thank you."

She smiles, a bit too widely, then goes serious. (Mouths should not have that many teeth.)

"I can, as previously mentioned, find the paths to things, including goals. Tycho is loosely clairvoyant, though Milliways interferes with that, and his power feeds mine. The only things we've found so far that interfere with Tycho's ability are powerful anti-clairvoyance magic and reality-warping. We can separate and act independently of one another, though if one of us leaves Milliways and the other stays time will be synced even with the door shut. I can move between dimensions on my own, though taking passengers is... Not usually beneficial for the passenger. I can, if I'm familiar enough with an object or person, track it, even across dimensions. A physical part of it helps. I also have an extensive network I can call upon, though that can take a while and comes as a surcharge."

She's not mentioning everything. Mostly about how her anatomy is... somewhat not, making her difficult to kill. And how she can somewhat track an object's origin; mentioning that tends to discourage people from paying her in anything other than credit.

"For a previous case... A woman from a highly magical world came in. Her world was being afflicted by a magical blight, powered by a god of undeath. She needed help identifying the source of the blight, killing his avatar and mortal servants, preventing him from reentering the world at least temporarily, making sure the credit went to her, and while she was at it becoming immortal. I guided her in where to seek allies both in her world and others, where to find powerful enough weapons native to her world but since forgotten, how to most efficiently and quickly obtain the maximum power level possible in her magic system, and how to seal dimensional barriers to hold back the god once he was thrown out. Her native magic permitted immortality, but the only known methods turned you into a withered husk or a skeleton, so I helped her develop a ritual to make herself less complicatedly immortal."

"Less expensively, another case was a revolutionary who wanted to win her war with minimum casualties and keep her nation stable after taking it over. I was able to do that with only what was present in her origin world. I guided her in challenging the leader of the other side to a formal duel, with the war as its stakes, and making sure the outcome of the duel was broadly supported. Then I identified who she should appoint to various offices, sorting for both quality of work and appeal to the populace, and which policies she should initially put in place to achieve her goals for the nation."

Contessa pays impassive attention to all that, and nods at the end. "And what sorts of—prices—do you charge?"

"Varies fairly widely. I commonly ask for a favor, never exceeding the original effort put in. Items, especially magical or scientifically advanced ones. I accept payment in stories, too - one person paid me with the collected works of their entire civilization. Milliways credit is acceptable, too, though usually works out to be more than an item would be worth. What you're trying has a large effect, too - god-killing is on the expensive end, self-improvement is on the cheap end. In credit I usually charge anywhere from one thousand to one hundred thousand dollars for something that doesn't take much time and only involves the resources in a world itself; significant investments of time and resources on my part cost more. The revolutionary paid me mostly in Milliways credits, with a few items thrown in, and her fee was around the five hundred thousand mark. The god-killer paid me almost entirely in powerful magical items, which ranged from worth four hundred thousand dollars to eighteen million, in addition to two priceless artifacts. I have accepted payment entirely in favors on occasion, and if a situation is critical enough I am willing to delay discussion of payment. I have done pro-bono work once, when a planet was in eminent danger of destruction."

"I see. Where does your magic come from?"

The woman is human with only minor changes - probably from an Earth, though Tycho's not sure - so that reduces the amount of context Sarah needs to give, at least.

"I'm from an Earth; it was fairly normal and magicless for the vast majority of it's history - the only thing different from average was the presence of daemons, and plenty of Earths have those. Late one century, a... Thing appeared above our world. Some called it an eldritch abomination, or a Lovecraftian monstrosity, or a malevolent god. It was heavily wounded, bleeding into the atmosphere. People directly under its shadow, or who spent too long looking at it, started going mad. Animals too. Some started speaking in tongues, a few became violent, most were simply traumatized. We more-or-less came together as a people to attack it once we realized what it was doing - waged a fairly short but brutal war. Managed to push it over the edge. It broke up into pieces when it died, which then fell to Earth. Mostly along a band under where it'd been orbiting, a hundred forty miles wide. Some of the pieces struck cities, some the wilderness, most fell into the ocean. The areas around the larger pieces were quickly warped, people dying, animals turning into monsters, plants growing in impossible shapes. People who'd lived nearby the fallen pieces slowly gained powers over the next few years - and more as time passed. I left twenty five years after the Incursion; by then, a third of the remaining censused population had a measurable power, though if you looked at population statistics for things like disease resistance it's likely the total including minor powers was actually higher."

"How typical is your magic?"

"In the multiverse? Probably rare, though that might just be the landlords fucking with me. I've been here several decades and have yet to meet anyone else with the same power-origin. My specific manifestation, on my planet? Also rare, the powers tended to match people, and most people got something showier. And more obviously useful from the start. Though worlds whose magic has a similar theme of sorts are surprisingly common. I suspect that as people and worlds have templates, so do magics."

"Templates?"

"Some people have sort-of copies in other worlds. Them as if they'd grown up in different circumstances, or the same childhood but later access to different magics or people. Alts - members of a template - include but often go beyond 'from the same world that had a divergence point after their birth.' I haven't met any alts of myself yet, but I've run into alts of some of my acquaintances from my home world, with a slightly suspicious frequency. You're the first you I've met, though. Worlds also - copy themselves. 'Earth' is a common template; many worlds are variants on it - a number are Earths-with-secret-magic, which manage not to diverge until fairly late, despite having different magic systems."

She nods, slowly. "You do not age, also?"

"I don't. Most people in my world did."

"Is that part of your magic?"

"Yes. Seems to be related to having a stronger power."

"Other people with stronger powers like that are also unaging?"

"Not entirely sure. It'd only been two and a half decades before I left, and most people with strong powers died rather quickly." All too often by being killed by their ex-allies after monstering. "I left, and have been being careful to not die, so I don't seem to have aged. But I was fairly young when I left, so. Might just be slowed down."

"Died quickly?"