"Firstly, that's impossible, secondly, when it comes to dark magic, there are no charitable interpretations." 

"Well, I've absolutely figured it out for things that we can tolerate being scorched as the dhar exits. I can demonstrate if you like?" The Acolyte gestures to any suitable piece of debris that he could excise the dhar from, if there is one.

The woman will watch a demonstration (on, say, a barmug, or a human skull she just happens to have with her) with the wariness of someone who has received an offer to see the nice bit of plutonium a stranger has in their backpack. 

The Acolyte will proceed to tear the dhar from the skull (never waste a good mug). He’s been practicing and experimenting, so it’s not the black conflagration that it once was, now more of a dark smoldering that nonetheless still expels the taint, and still leaves the skull scorched (though not reduced to cinders).

”It is a work in progress.”

"... nonetheless, you are making progress on an impossible goal. How?"

“I am acolyte of the principle of Fire, whose Flanes are division. Or more simply, I am applying a kind of magic that seems foreign to this land, perhaps this entire world.”

"This is not a feat of Aqshy. Tell me more about this god of yours." 

"i don't know if it is a god, at least not as they are here, but.."

The Acolyte will expound on Fire for as long as this person will listen, whether about its philosophy, the limits of its magic as he knows them, the limits of his own expressions of its aspects, and so on, so forth.

She will listen quietly, happy to listen to someone discussing their power without having to give away any of her own. Obviously they're holding stuff back, but who wouldn't? With that in mind, this guy is pretty terrifying, though.

"So, uh. You're pretty strong then. What're you going to do when they come from you? You still can't beat them all." 

"Call me an optimist, but I am hoping that people will see the value in what I can do, and even more in what I can teach, and find it worth what I understand appears to be considerable risk."

He scratches his chin and chuckles a little. "That, or to run very quickly."

"When all the forces of the so-called righteous and pure are at your heels, I do not think you will like the places you can run to very much." 

He considers it for a little longer. "I do have a friend who seemed reasonably out-of-the-way, a ways north and east of here who I might be able to stay with, if trouble comes soon. Still, I spoke of Fire with the Veranites not long after I arrived here in Praag and they seemed not too bothered by it."

"Did you mention your experiments with Dhar to them?" 

"Ah, no, I suppose not. I assumed that working towards a means of purifying it would be acceptable at the time."  He pauses to think again, "I suppose I'll head back to their temple and ask them about it after we part ways."

"I would not, if I were you. They will assume you are already corrupted, and mark you for death." 

"Hm." They didn't seem that over-eager, when he last visited them. He just handed over his books and it all seemed to go quite well honestly. "I've had a positive experience with them already, so I'm somewhat doubtful, but I'll take your piece into consideration."

"Never underestimate the ability of religious fanatics to kill and burn and destroy with the goal of 'purifying' the world." 

The Acolyte nods and frowns noncommittally. "Very well. Is there anything else you wished to speak or learn of?"

"Just like. Have some circumspection. If you get a blood inquisition called down you're not the only one they're gonna hurt." 

He nods again. "Alright. I'll try and be a bit more discreet."

Then, unless he's stopped, he'll head out, get back to work, and take some coin from his pay for that day to send a message to the temple of Verena, mentioning that he's developing a technique for dhar taint mitigation and he'd like to have it examined and checked against any records or standard they might have for such a thing. If this draws their ire as quickly as the mysterious woman thought it would, hopefully having it be a message would give him time to run.

She will not prevent him leaving. 

The Venerans will respond with a message saying that they have no such standard because that's impossible and if he thinks he has a tactic for doing so he's probably being lied to by something and should stop interacting voluntarily with dhar in any way at once (because it's a cognitohazard that encourages further interaction and further corruption), and if he does not, he might be declared a chaos sorcerer and dealt with appropriately. 

He'll send another message (never forget to tip the messenger, also) that the special magic he mentioned to them earlier seems to make the problem tractable. He is not in communication with any entities he's encountered so far, he's arrived at this technique through his own experimentation. He'd like to demonstrate it for them, if they're willing to prepare a testing stage that they think is safe, and if they find it unacceptable he'll naturally stop this line of research.

They would want to have a miracle-worker watching at a minimum, and ideally a whole bunch of properly guaranteed magisters (left unspoken how this is what they would want, to take the acolyte out if they had to do that), and there aren't any Veneran miracle-workers in the city, and doing such a test would violate (or at least, come within spitting distance of violating) the oaths sworn by magisters of the imperial wizards colleges. Really no point doing this study without someone capable of actually perceiving and analysing dhar, though. 

Fair enough. He'll send one last message that he'll table that line of research until they have the resources and organizational will necessary to put such a test together, and that he understands if that won't happen for a long while, if ever.

He will still see if he can get a chat with Butcher Bigfeast and observe a dhar taint cleansing in the ogre tradition, but in the mean time, he will switch to meditating on Determination and see if he can make some progress from that direction instead. Maybe he can find some people who are new to Praag (other than himself, maturally) at the docks or one of the city gates, and attempt to observe how they resist the city's curse.

Their response comes, instead of a messenger, but with one of the bronze-armoured templars, here to make sure he keeps to his word regarding ceasing this line of research.