“You can’t be serious…” The blonde girl said, looking at the imposing building above her.

“Oh, you worry too much, cutie~” Lisa said in response, striding up to the hotel’s front door. “Didn’t you agree to be my little helper, returning overdue books?”

“I mean, I did…” Lumine said, swallowing hard. “But is it really worth starting trouble with the Fatui of all people?”

“I am the librarian of the Knights of Favonius. If I don’t take it seriously, then why be in that position?”

Lumine had only been in Mondstat for a short while, but she’d mostly enjoyed her time. Even if her work with the Knights of Favonius often felt like an unnecessary detour from finding her brother, it was good to do the right thing, to help a place instead of simply pass through on her travels. She’d offered to help Lisa in her rounds more than once by this point, and there had been some misadventures in the recovery of overdue books before. Lisa did take her duty seriously - Lumine shuddered a bit at the recollection of the last unrepentant tardy returner.

But this was a different matter altogether. But this was the Goth Grand Hotel, base of the Fatui in Mondstat. While Mondstat was, technically, on friendly terms with Snezhnaya, and the Fatui were officially the foreign affairs branch of the frozen nation’s government, the truth was rather more complex. Or rather, not very complex at all, just politically volatile - the Fatui were spies and saboteurs undermining Mondstat in the hope of claiming it for their Tsaritsa.

While Lumine and her allies had stopped them once, they continued their tricks and treachery under the thinnest guise of aid and the aegis of diplomatic immunity. The Knights of Favonius had an especially poor relationship with them - which made Lisa barging into their territory an action ranging between ill advised and absolutely nuts.

“I’m just saying, maybe you should see if Jean can talk to them?” While she had to try, Lumine saw that look in Lisa’s eye - she had set her sights on something and was going to get it no matter how many people she had to shock into submission.

“Hey, get outta here!” A man in a Fatui mask said as the pair approached, stepping between them and the door. “This is Fatui territory. If you ain’t got business-”

He wasn’t allowed to finish as Lisa summoned her spellbook, and… thwacked him on the head with it. Not even using lightning. He was so surprised he couldn’t defend himself, being thrown aside easily. Lumine winced. As much as the Fatui probably deserved it, she wouldn’t wish Lisa’s wrath on her worst enemy.

Lisa shoved open the front door, and stepped forward towards the receptionist’s desk. Around the room, Fatui agents turned and stared, looking up from their dinners or their books or whatever else they were doing, to look at her. “Hello,” she said to the stunned Fatui manning the desk, “Is one ‘Miss Catarina’ present? She rented a book from the Knights of Favonius library and is long overdue.”

The room was silent for a long moment. “...You… are here for an overdue library book.”

“Yes, that’s right.”

“And you’re aware of where you are.”

“Yes.” Lisa said. “Do I need to repeat myself?”

“No need, no need.” Another woman said, coming from down the hall. “That would be me. I can bring you to the book, if you wish.”

“Finally, someone who isn’t being difficult.” Lisa said.

The receptionist looked at her. Her eyes were hidden behind her mask, but she was clearly surprised. “Catarina, you’re really going to just… let her barge in her and do what she wants?”

Catarina raised her hands in a placating gesture. “Relax, relax. I can handle this.”

“I’m sure.” Lisa said. “Come on, cutie, we have a book to return.”

“Ah, I think I’m going to have to ask that she remain here…” Catarina said. “You understand. My boss will have my head if I show more people this place than I must.”

Lisa frowned, but nodded. “You can guarantee she’ll still be here when I get back?”

“And unharmed.” Catarina confirmed.

“Lisa, I have a bad feeling about this…” Lumine said.

“I do have to get that book, you know. It’s distasteful, but duty must be fulfilled, and obligations met.” Lisa said firmly. She would get that book, even if she had to call lightning on the entire building.

“Quite.” Catarina agreed. “You may wait here, while I see to the woman’s needs.”

Lumine crossed her arms, but didn’t argue. She wasn’t exactly in the best position for it.

Lisa followed the Fatui further into the hotel, being guided to a lounge area. “Please, take a seat, while I take a moment to find it. I believe I’ve left it on this bookshelf…”

Lisa was frankly surprised they were being so cooperative. She had been prepared to fight for it, but it seemed that wasn’t going to be necessary. “I appreciate how cooperative you’re to being. Lumine was talking about how you’d never return it, just to spite the Knights.”

“Oh, of course. While we’ve had our issues, I at least believe we are above such pettiness. I was simply so engrossed in the book that I forgot to return it.” Catarina ran her finger along the spines of the books, and nodded as she took one out. “Yes, I believe this is it…”

Lisa nodded, looking at the book - it was an unassuming thing, with a worn leather cover that spoke of it’s immense age. It didn’t have so much as a title, let alone the author’s name. “That’s definitely it.” Lisa said, nodding. “Never read it for myself, though…”

“It’s an interesting one, to be sure.” Catarina said. “It’s an old book telling of ancient electro-magic. Quite intriguing, really.”

“Maybe you can rent it again soon. For now, I’d like to have it back.” Lisa extended a hand.

“Of course.” Catarina said. Instead of the book, she offered her own hand, shaking Lisa’s firmly. Lisa was about to ask what she thought she was doing, as she saw a blue gem accessory on Catarina’s hip suddenly glow. A Vision, active.

The lightning began to course through Lisa’s body before she could move, causing her to jerk and seize in place. Catarina maintained contact, sending a constant stream of shocks through her nervous system. “Feeling distraught? Betrayed? Well, good. It’s what you get, for thinking you can demand anything of the Fatui. But I, and my masters, are very generous. I won’t kill you.” Catarina squeezed Lisa’s hand harder. “No, we’ll do something else. That book you gave us… it had some interesting spells I wanted to test. Consider it a reward for helping us so much.”

The lightning moved with precision and purpose, in a way that was different from the normal uses of electro. It wasn’t just a random attack, and somehow, it did no damage to her body even as it coursed through her. Lisa, of course, wouldn’t be seeing how it went to her brain. Catarina reveled in her shock and confusion, as she guided the electricity in its purpose.

Lisa found she couldn’t help but be impressed, somehow. Her thoughts and wits were scattered, but that stood out. Such fine control, such skill. Even with an ancient magical tome guiding her, Catarina would not be able to replicate it were she not a master of Electro. A lesser magic user would have fried Lisa to a crisp by then. The Fatui had some excellent mages under their command, it was clear. The thought was invasive, suffusing every part of her mind. She… was impressed by the Fatui? That wasn’t right, was it?

A little twitch of Catarina’s finger, a bit of lightning to the right part of the brain, and the offending thought was snuffed. No, she wasn’t impressed by the Fatui. She admired them. Their power and skill. How could she not, as one mage to another? She had some skill in the craft, but nothing like this. These thoughts were rewarded, as a bolt of pleasure rocked her body. She was sure she could figure it out, had she access to the book.

This manipulation would be a bit harder, Catarina thought - she moved two different arcs at the same time, and Lisa’s thoughts changed. She was good. One of the best in Mondstat. One of the best electro mages ever, even. Was it egotistical if she was right, she thought with a smug feeling, and of course not even capable of thoughts beyond what Catarina directed her too. She was one of the best - which made it all the more impressive that she couldn’t do what Catarina was doing. Jealousy filled her, but so did awe. She had to know how to be so skilled and strong as Catarina. As she thought of the electro mage, that pleasure redoubled, encouraging and reinforcing the thoughts. It felt good to think like that, so she would.

Lisa had always been confident. But confidence wasn’t what Catarina wanted from her. A smug feeling of arrogance and superiority would be more appropriate for her new role, and that was what she got. But not to the point she wouldn’t obey. No, she was arrogant, but not stupid - she couldn’t do what Catarina could. So obviously, she would want to learn. Catarina moved her power to tangle with the web of memories, and had her most difficult task ahead of her.

Lisa wanted to learn from Catarina. So, she thought, it was a good thing she was her apprentice. Wait, apprentice? To a Fatui? Was that - of course it was true. She had joined them recently - no, years ago - no, since she was a child. She had always been a member of the Fatui, ever since she was found to have the potential to use a Vision at a young age. Catarina was her enemy-rival- superior, her teacher, her mistress. The Knights of Favonius? Well, they were her friends- no, her assignment. She’d infiltrated them… right…

Catarina carefully wove the web of Lisa’s new life. It was hard to rewrite an entire identity, so it was primarily her youth that was changed, until she was assigned to infiltrate Mondstat and the Knights. After that, it was mostly a matter of adding in a few meetings with handlers, a little tweak of her opinions on the members of the Knights.

The spell was complicated and difficult, messing with the very workings of Lisa’s brain - but well, Catarina had had some practice. Two of the Fatui agents in the lounge, making sure the brat Lisa had arrived with didn’t leave, were the results of her practice. A bit dull in personality, a bit dumb, but worthy sacrifices to get her to this level of control.

Catarina finally withdrew her hand, and let Lisa sort herself out. She stood there in a daze for minutes, in a haze of pleasure as her own body reinforced and cemented the new identity that had been forcibly instilled. While it was a magically caused, the book had taken great pleasure in noting that due to how it worked by rewiring the subject’s brain, the results were permanent - when Lisa came out of her haze, she’d be a Fatui agent through and through.

The mage slowly came back to reality, blinking as her body finally settled. “What… where…?”

“Hello, apprentice. You had a report for me? And you brought that… honorary knight, with you, yes?” Catarina said.

Lisa nodded absently, Catarina’s words prompting her mind to fill in all the blanks. “The Knights haven’t even started to suspect me.” she said, with a smug grin on her face. “I’m even in charge of their library, with unfettered access to the restricted section.”

“Impressive.” Catarina nodded. “You’ve done well. I’ll reward you with a lesson later.” she said.

Lisa shuddered with pleasure at the thought. She loved Catarina’s lessons… they were so… intimate…

“Now, what of the girl you brought? I was surprised you didn’t come alone.” Catarina prompted.

“Oh, I had a delightful idea. Everyone saw her fight that dragon, yes? Everyone knows she’s one of Mondstat’s protectors, right?”

“That’s right. So?” Catarina asked, curious what sort of devious mind was left to her new follower.

“I heard the others talking about claiming credit for running off Stormterror, but since so many people saw her, that would be a problem. So I thought, wouldn’t it be even better propaganda, if it was true?”

“I’m listening...”

“I know that you’ve been practicing that conversion spell, and you being you, have probably perfected it. Wouldn’t it be the best propaganda if Mondstat’s hero turned out to be a Fatui agent the whole time? And besides, I’d love to have a cute little henchwoman for myself~”

She was perfect, Catarina decided.

“I like that plan a lot. First, though, I want you to get dressed. I want to see the despair, the betrayal~”

“Oh, that sounds exquisite, boss…” Lisa licked her lips, imagining how that cutie would react to seeing her in full Fatui garb…

An assistant brought her the clothes, and she got dressed. Getting rid of her annoying civilian clothes, she pulled on the black and purple bodysuit. She loved how it clung to her body, how it exposed just the right amounts of skin… it was an unfortunate part of her job that she had to wear her usual dress to avoid raising suspicion. She followed the bodysuit with the elaborate robe of a Fatui Cicin Mage, with it’s large amount of fluff, big sleeves, and a nice hood. The final touch, of course, was her mask. It was a simple thing, covering just her eyes and some of her nose - she wondered, how long would it take Lumine to recognize her beneath it?

“Looking good, Lisa.” Catarina complimented.

“Of course I do.” Lisa said, “It’s good to be back in my uniform…”

Catarina stepped to the door and opened it. “Come now, apprentice. We have a cute do-gooder to teach about the glory of the Tsaritsa~”

Lisa grinned savagely, and followed, fantasizing about what she’d do with Lumine helpless before her...