So, here's another potential story idea. For the first time in a while, it's a Baldur's Gate 3 crossover. And those who follow my stories will no doubt notice that it uses, in many regards, almost the same premise as my oneshot Whoops! Or How to Stuff Up a Summoning (plug, plug). In other words, a Harry/Karlach story, where Karlach narrowly avoids getting an Infernal Engine instead of a heart.

That oneshot was a pilot episode of sorts, not for a fic per se, but for the concept of a fic with a similar premise and pairing. And Karlach is genuinely the nicest and sweetest of the female main characters in the game, despite being also a boisterous berserker. Don't get me wrong, Shadowheart is my main waifu from the game (my current run has just succeeded in cementing their relationship), and I am also considering a story pairing her with Harry. Then again, believe it or not, I am also putting serious thought into pairing Harry with Orin the Red (and yes, I have ideas for how it is possible without turning Harry into a Bhaalspawn murderhobo or something as bad). Lae'zel's still a possibility, but her xenophobia put me off, while Mizora is Bad News. Other characters who caught my eye are either in an established relationship, may have incompatible orientations, or both.

But Karlach got the rawest deal out of pretty much every playable character, at least in terms of what will happen to her after the Absolute is dealt with (Astarion has gone through worse beforehand, but he can at least live in the shadows and be nocturnal, the Dark Urge can resist his or her Bhaalspawn impulses, and Shadowheart can earn her happy ending). She either has to become a Mindflayer, allow the Infernal Engine to explode, or return to Avernus. So, with a chance of giving her a better life and story, well, it took some work, but hopefully, you'll like this.

Just so you know, though, there's no guarantee this will become a full fic. In addition, I literally finished Act 2 of the game only yesterday, and maybe playing more of the third act later on after taking a break from the game might inspire me for something else. And in some ways, this also feels like an also-ran of my Harry/Barghest story, though Karlach and Barghest only share some similarities.

But there's so few Baldur's Gate crossovers with the Potterverse, and aside from my oneshot, only one's a crossover with the third game. So I hope to do at least one longer fic in this crossover one day. Hope you enjoy this effort...

WIZARD AND TIEFLING

CHAPTER 1:

A TIEFLING IN MAGICAL BRITAIN

The multiverse is vast, varied, and often weirder than you'd imagine, especially when magic gets thrown into the mix. There's a number of varied types of magic, each with its own unique way of getting the fabric of reality to cry uncle. However, when these differing schools of magic interact, the results can be…interesting. Namely, ranging from simply cancelling each other out, to some rather cool pyrotechnics (though not so cool if one happens to be caught in the middle of said fireworks), or causing horrors from beyond known spacetime to invade reality.

A particular problem is that related to demons, devils, and the like. There's almost as many pantheons of diabolical creatures as there are universes to house them. But the sort who like to wreak havoc or give power to greedy or desperate mortals in exchange for things they shouldn't give away are manifold, and like to get as large a customer base as possible.

So it was with Zariel. Once upon a time, Zariel was once a Solar or angel under the aegis of Lathander, the Morning Lord. But to cut a long story short, she fell from grace, becoming an Archdevil ruling over Avernus, the first layer of the Nine Hells. Oh, and she also did so with violence, brutality, and being an all-round rather not nice person.

Yet her rather infamous reputation didn't stop people from making deals with her. People whose desires outweighed their sense. And making deals with Devils like Zariel or those under her never ended well.

Take one Enver Gortash. He was the victim of being sold to a Devil, or rather, a Cambion by the name of Raphael, and by his own parents no less. Gortash suffered greatly as Rapahel's pageboy, but eventually came out the other side. Gradually gaining influence within his native city of Baldur's Gate, Gortash began accumulating power both covertly and overtly, becoming a publicly-famed 'military advisor' while controlling much of the criminal element within that city.

Having not learned from his parents' example, Gortash had dealings with Fiends. And he would use every bargaining chip he could to get the most benefit he could out of such deals. Even if it meant betraying those who were otherwise loyal to him.

Take, for example, Karlach Cliffgate. A young Tiefling woman, she herself had Fiend heritage, even if she was a genuinely moral and decent soul. She joined Gortash's service hoping to serve a liege lord and earn some money, and Gortash impressed her…right until he sold her as a token as part of a deal with Zariel herself.

In many timelines, Karlach's fate was an unhappy one. Her heart replaced with an Infernal Engine, a dangerous artifact, she would be doomed to either return to the Hells should she ever escape them, or else die burning as the Infernal Engine overheated in the Material Plane if she did not return. And despite her Devil-like features and being forced to fight in the Blood Wars for a decade, the young Tiefling was a good and moral soul who kept onto her heart (at least metaphysically), despite her love for battle.

Yet Zariel made many deals across many timelines. Many were the fools who blundered into her web. And there were many ambitious and malevolent idiots on a certain world called Earth amongst them. The magic of this world was different to that of her usual haunting grounds to some degree, even if it bore a resemblance to some wielded by Sorcerers.

Unfortunately, given the way the ritual used to summon Devils acted, different magic systems could interact in odd ways. Hence why, when a certain fool summoned Zariel at the same time as she was making a deal with Gortash with Karlach as coinage…well, things buggered up. And in an interesting manner.

But in many ways, it seemed to be karma finally balancing the universal scales, at least in this timeline. Not that Karlach would know it in this one, not for many years. After killing her summoner in self-defence, she was captured and kept in the custody of the Circus Arcana, already noted for its infamy in treating its performers and prized specimens poorly.

And yet, salvation would eventually be sent her way…

"I'm not sure why you wanted me here, Croaker. Especially as I have been given 'administrative leave', which is fancy bureaucratic wording for saying I've been benched, pending my being kicked out of the DMLE and being blacklisted from every Ministry job out there. And as much as I would love to work for you instead, I'm not sure I am qualified for the Unspeakables."

"Oh, all you need is a modicum of intelligence, a reasonably open mind, and a tendency to ask the right questions, Harry. Besides, Percy Weasley has an eminently punchable face. If you don't mind, I'd like to take a copy of that memory for my personal Pensieve. If I do recruit you, he has no right to object."

"Not that it'll stop him from trying," Harry Potter muttered sullenly as he followed Saul Croaker down a corridor in the Department of Mysteries. "He's always been an anal-retentive arsehole, but since managing to get Shack booted out, he's been getting even worse and worse. But exposing Delphi's parentage in the Prophet…he had the gall to say it wasn't him, but I know that of everyone in the know, only he would do it. As it is, Andromeda had to explain things to Delphi, about how her honorary uncle killed her psychotic parents. Try explaining that to a seven year old. I couldn't do it, and I'm glad I trusted Andromeda to adopt her. Honestly, I should have hit him harder, and more times."

"You're lucky that he didn't press charges, though locking up Voldemort's vanquisher wouldn't look good for his reputation," Croaker said. "In any case, because you were suspended from the DMLE, you missed a rather interesting raid on the Circus Arcana."

"Circus Arcana?" That rang a bell with Harry, but he wasn't sure why.

"A rather dubious example of a magical circus. It's been around for a couple of centuries, and its reputation has waxed and waned with its owners. I actually came across a tidbit that'd interest you. Nagini was originally a performer in that circus, a Maledictus who was said to be a rather kind person before her curse overtook her and Voldemort took her as a pet."

"I find that hard to believe," Harry remarked bitterly, remembering Nagini's malice. If she ever had been a good person, the good in her must've died long ago. He knew what a Maledictus was thanks to Hermione once lecturing him on the subject, but the thought that Nagini had once been a good person was strange to him.

"In any case, there were more than a few performers who were kept there against their will. Most are at St Mungo's awaiting treatment prior to be sent back to their homes, in Britain or abroad, but…we found a rather special case. She's from further afield than we thought possible."

"Further afield?"

"As in she comes from another world entirely." On Harry's shocked look, Croaker nodded. "Oh yes, we get more than our fair share of travellers, intentional or otherwise, from other worlds. One you have to watch out for is a chap called Kischur Zelretch Schweinorg. But this woman is an unintentional traveller from another world. Said world is called Toril. Technologically and culturally, it's closest to medieval or Renaissance times for the most part, with some exceptions, though magic is wielded openly, unless it's particularly forbidden magic. Beings of all kinds live openly on that world, even if racism is still prevalent. Our young guest is a case in point. She is a Tiefling."

"A Tiefling?"

"A being with some sort of Fiendish influence in her bloodline. In other words, either one of her ancestors banged a Devil, or made a deal with one, and mutated their bloodline. Now, I should add that, given our few visitors from Toril and at least one expedition there, Tieflings are as morally diverse as humans. Our guest may look like a Devil, but I am satisfied that she is actually a morally-upstanding person, and we're lending her a special ring to disguise herself as a human. Anyway, unfortunately, during that raid on the Department of Mysteries back in '96, a lot of our library was either stolen or destroyed by opportunistic Death Eaters while you were trying to get your prophecy. We do have enough notes to be able to start work anew on a ritual that can send her back to Toril, but it's going to take a lot of work, months if not years, and our guest needs somewhere to stay."

"And I'm being conscripted?" Harry asked irritably.

"I have alternatives, Harry, but you were the best. The Rookery isn't as isolated as Potter Manor, and Hermione's apartment isn't discreet or roomy enough. Our funds are large enough to offer a reasonable stipend for living expenses. Think of her as an overseas exchange student. What's more, she's willing to pay her way. She had started doing mercenary work, before her first proper employer decided to sell her to an Archdevil of her world's Hells by the name of Zariel. From what I gathered, Pansy Parkinson was the one to try and summon Zariel to our world at the same time."

Harry's mind went back about five years, and chuckled uneasily. "Huh. Let me guess, she actually killed Pansy? Her family found her crushed beneath a toppled bookshelf. They claimed she was murdered, but given all the demonology paraphernalia, well, the Parkinsons had a lot of explaining to do."

"She killed Pansy Parkinson in self-defence, though I doubt any court in the wizarding world would see it that way, so I suggest you be quiet on the matter. Our guest loves a good fight, but she doesn't go out of her way to be a killer unless she has to fight for herself or others. Anyway, we're almost there. I'll allow you to introduce yourselves."

Harry nodded, even as his mind wandered. If Croaker was right, and this Tiefling was a decent person, then looking after her could be a welcome distraction from matters. Percy's BS really rankled with him. Even though his relationship with Ginny fell apart, they still remained friends. The same went for Ron after his relationship with Hermione tanked.

But Percy? He was the black sheep of the family, that damned wannabe politician. Harry regretted giving that officious prick anything like the benefit of the doubt, especially after what he did.

Harry's thoughts were chased away when they came to a door, which Harry recognised as a training room, from when Hermione dragged him down here to help him with his own Auror training. Animated mannequins could be sent against those fighting in there. And Harry heard the grunts of exertion, of a young woman.

They opened the door to reveal an ongoing battle. A mock battle to be sure, but a mannequin smashed into a nearby wall, nearly bisected. Others lay at the feet of the woman fighting the other mannequins.

And what a striking woman she was. Her muscular body was clad only in a tank top and jeans that seemed almost painted-on. Her movements were short, sharp and violent, speaking of some experience.

And yet, she looked nothing more or less than a female Devil.

Her skin was scarlet, a bright red. A pair of ram-like horns protruded from her forehead. Her ears were pointed, her teeth sharp. Her fingernails were more like short, sharp claws. A spaded tail protruded from her backside. And her eyes were golden with scarlet edges, the pupils a sharp slit.

Yet she was attractive, despite her demonic features. Her muscular figure was a picture of athletic beauty. And her face, while currently set into a snarl of exertion, was surprisingly beautiful, framed by a mess mane of black hair.

The Tiefling then said, in what sounded like a British accent, "Okay, enough." As the mannequins reassembled themselves and stacked themselves against a wall, she muttered, "Dammit, I'm rusty. I worked out as much as I could in that cage, but…" She looked up, and noticed them.

Most of the doubts Harry had were chased away when he saw her expression change. The aggressive frown was chased away by a friendly smile. And not the oleaginous sort of thing he would expect a Devil to make, trying to worm one's way into one's good graces. It was a simple casual friendliness. For some reason, he was reminded vaguely of the late Nymphadora Tonks. It was strange and yet so reassuring to see such a human expression on her face.

"Hey, Saul," the Tiefling said cheerfully. "Thanks again for letting me use this room. A shame you couldn't make the dummies look like Gortash. I would've loved to slice that treacherous bastard up."

Harry looked to Croaker, who chuckled. "When you allow us to view your memories in a Pensieve, I'll see what I can do. Anyway, this is Harry Potter. He hasn't agreed to host you yet, but he's considering it."

"Yeah, well, that figures," the Tiefling said, approaching them, and holding out a hand. "Hey there. I've heard a lot about you, Harry Potter. The name's Karlach Cliffgate, formerly of Baldur's Gate. Nice to meetcha, soldier."

After a moment, trying not to bristle at being called 'soldier', Harry took the Tiefling's hand. It was just a little warmer than most hands he had shaken, and a touch on the sweaty side, but despite the strength he could feel in the hand, she was quite gentle. Firm, but gentle.

They didn't know it, but this meeting marked the beginning of a bond between two unlikely people from two different worlds. A bond that would have a marked effect on a brewing plot that would one day potentially affect the fate of many worlds and planes. For better or for worse, it began here…

CHAPTER 1 ANNOTATIONS:

Harry's met a Karlach who has accidentally ended up in the Potterverse. But can they learn to trust each other?

Now, in case you're wondering why Karlach is so cheerful after five years being locked up in a circus freakshow, keep in mind, she's still cheerful (even if it's partly a mask) after A DECADE IN AVERNUS! As in, a layer of Dungeons & Dragons Hell! Five years in a circus freakshow is a doddle, especially if the Circus Arcanum didn't mistreat her too badly. Oh, she's got some psychological scars, but given that Croaker showed himself to be a decent human being to her, she's recovering fairly quickly.

No numbered annotations this time.