True to her word, Lady Aztecatl showed up at Hogwarts the Sunday after the trial just before noon. Albus had a tea service arranged for the meeting, and all of the portraits in the Headmaster's office were occupied. She knocked softly on the door at twenty minutes before midday. It swung open for her and she stepped through, this time resplendent in a rich turquoise gown and matching robe. Pearl-drop earrings winked out from amidst a few free wisps of hair, the rest of which was twisted into a low, loose bun at the nape of her neck. The same feathered serpent he saw on the day of the trial lay draped across her shoulders like some absurd living boa. Yolotli and it hissed back and forth to each other. Once more they conversed, dunking him in chilly fascination with their words.

Dumbledore, as nonchalant as at their previous meeting, smiled graciously and gestured at the remaining seat in front of his desk. "Please sit, my Lady. Have some tea if you would like." She grabbed a scone off of the tray and made herself a cup, then sat down beside Severus. The Lady arranged her skirts about her as she settled into the chair, her teacup cradled against her. She lifted her head and met their curious stares unflinchingly. "I have propositions to make. Some concern your Potions Master, although one also concerns you, Lord Dumbledore."

Dumbledore chuckled. "I am only Lord Dumbledore for official business, my Lady. Please, call me Albus."

She huffed in amusement. "I suppose so—Albus." She focused on Severus. "May I call you Severus?" Severus felt darkly like the question was just for show since someone like her could call him whatever she liked and get away with it. Yet she waited for his jerky nod of consent before moving on to the purpose of her meeting. "My first proposition for you, Severus, is to teach you what arts I know, namely Alchemy and Blood Magic, but perhaps also other things, like Elemental Magic."

Severus' spine straightened instantly. Alchemy hadn't been taught within the walls of Hogwarts since Dumbledore's time, neither as classes nor under private tutelage. Neither Elemental Magic nor Blood Magic were taught as their own subject at Hogwarts at all. Severus watched the Lady more calculatingly than before. She must want something great indeed to offer something so valuable and tempting.

The Lady took a sip then continued. Dumbledore appeared to be waiting patiently for the right moment to speak. Judging by the wrinkles on his forehead her offer concerned him. "My second proposition is to do with your personal life. I am willing to facilitate communication between you and my dear friend Eleonor. Eileen May accompany you if she wishes, but I have no way to contact her directly and approach her. It is far easier to speak with you and have you speak to her in turn." Severus inhaled deeply, unable to hide his reaction as the Lady took another sip. "What are your thoughts? Albus? Severus?"

Severus pursued the, in his mind, more puzzling proposition. "Why?" He pressed. "Why teach me any of your arts?"

"You are powerful and intelligent, and you have great potential and many natural talents."

"For a halfblood?" Severus couldn't help but ask bitterly, hating himself for looking a gift-horse in the mouth. She was offering to share her knowledge of Alchemy, Blood Magic, and Elemental Magic, and his abrasive personality might ruin it for him! He sneered to himself. He hoped he wouldn't be too unpleasant for the Lady. He appreciated not being in Azkaban as much as he realized what her proximity to him might do for his own social standing. He wasn't a ruthless social climber like Lucius, stabbing any and every person he perceived to be in his way in the back for even a slight foothold, but he recognized that if others saw him as in her good graces, her protection even, then he might be shielded from the backlash that would surely come from the trial once more of the general public became aware of its outcome. Not all read the Prophet, after all, and the news would need time to circulate fully.

The Lady waved her jeweled hand dismissively. "Goodness no. I don't concern myself with someone's blood quantum the way some of your kind do. Pureblood, mixedblood, halfblood, mudblood—pardon me, Muggle-born," she corrected herself before either wizard could express distaste for the term. Severus could see Dumbledore had been even quicker to form protest on his lips than he had been, but she had modified her speech before either could speak. "I see power, potential, talent, and intelligence. You being a halfblood means nothing to me. You're as valuable and as worthy as any pureblood. In fact, I've met purebloods who can barely hold their wand or cast a simple Lumos."

Severus sat back in quiet satisfaction. He might not be instantly dazed out of his wits by receiving praise from her as some lesser, simple-minded wizard thinking with his prick might be, but a part of him preened all the same. The part of him that wondered what she wanted as payment overshadowed it, however. Even Dumbledore seemed to dread the answer as he asked slowly, "And what would you demand of him in return?"

Lady Aztecatl gave Dumbledore a coy look that Severus realized was simply a ploy to mask her cleverness. She wouldn't be the first woman to manipulate men's unfortunate fixation on her beauty to her advantage. Narcissa Malfoy and Giuliana Zabini came to mind as examples he knew personally, though thankfully he had the sense not to fall into their traps. "For sharing my knowledge with him? Or for reuniting him with his mother's family? Or perhaps even for my hand in his freedom?"

Dumbledore clasped his hands on top of his desk and sat back with a sigh as a chilly wave of apprehension broke over Severus. Dumbledore's response would not work to reassure him. "Any of them, my Lady. I'm afraid Severus is a valuable asset of mine and I can't afford to lose him. If any repayment you want for your...favors...involves something that could harm, maim, or kill him I'm afraid he will have to decline," Dumbledore admitted frankly, much to Severus' astonishment. Severus both resented the man for deciding for him what he could and could not do in a way that instantly denied him a vast wealth of knowledge, and felt grateful that he might protect him from any ideas the Lady had for repayment that might leave him in less than one piece.

The Lady gave him a disbelieving look. She sounded exasperated with Dumbledore in a way Severus could appreciate. "Albus, why on earth would I secure his freedom only to make it moot in the same week? Besides, Severus is perfectly capable of coming to a decision about something that concerns him."

"I have no idea what you consider safe, or more to the point, what you would consider harm. I'm only thinking of Severus' safety."

The Lady rolled her eyes. "Really, Albus, he will be perfectly safe with me. I'm sure he can hold his own, and I won't purposefully endanger him in any sense of the word."

"I'd still have your word."

"You shall have it. Or rather, Severus shall have it seeing as it is his safety and not your own. Now, as for what I would ask of him…"

Severus smirked at the look Albus gave her while her attention was elsewhere. Few people handled the Headmaster the way she did, and Severus found it incredibly entertaining. He gloried in the fact that she maintained his agency, acknowledging his will, his desires, rather than treating him the way Albus and the Dark Lord had: as a pawn and as a servant, but never as a full equal capable of thinking—and choosing—on his own. They underestimated him, used him, and took away his dignity. Lady Aztecatl, as socially and politically powerful as she was, spoke to him as if he could be her equal. Perhaps she had a cruel streak that he had yet to witness. Perhaps she had ulterior motives for offering to share her magical knowledge and heal his broken familial ties. Regardless, Severus wanted to say yes, though his Slytherin caution told him to wait to see what debt he would owe. The last thing he wanted to do was fall victim to his ego, insecurity and vulnerability again and end up chained to a third harsh master. Or in this case, a harsh Mistress.

Lady Aztecatl set her cup onto the edge of Dumbledore's desk and leaned toward Severus, intent upon him. She ticked off each favor with a finger. "Severus. First, I would require no payment to keep a good-hearted, innocent person free of a terrible fate such as you would suffer in Azkaban, except that you do not truly become as they already think you are. If you do, there will be consequences. Second, in exchange for sharing of magical knowledge, I ask only that you attempt to contact your mother, if she still lives, and convince her to have one meeting with Eleonor. She will be obligated to do nothing but show up, and if she is displeased she is free never to speak to her again. Eleonor is a dear friend of mine and only wants a chance to bring her family back together. Third, if you choose to have me set up a meeting with Eleonor to assess whether you can form a relationship, I demand nothing in exchange. I do it out of love for her, and love invokes no debts."

Really, her offer was generous, Severus mused. She could have asked for much more. She could have demanded his undying devotion or requested he bring her the still-beating heart of an enemy or obtain a priceless item. Instead she asked that he remain who he was (well, he thought, specifically she was warning him not to become a criminal or deserve her ire, since he was currently in her good graces, and that was an implicit warning he would heed with minimal encouragement), speak to his mother about speaking to his grandmother, and consider the remaining favor a freebie. His eyes narrowed in suspicion, but either she was incredibly hard to read or she had no plans to screw him over at some opportune moment. He bet more on the latter given how expressive she could be, and how open and honest she continued to be with the two of them. Then again, perhaps this was her way of building devotion. As much as she might insist that 'love invokes no debts', he felt quite sure that many would still feel themselves indebted to her, or grateful to her, and obligated to return kindness, if not also loyalty, to her in exchange for the things she gave. She could get what she wanted without twisting their arms, without bribing them, without overtly convincing them. She got her way ever so subtly, without ever being overbearing. What a Hufflepuff yet Slytherin way of doing things. Perhaps they all underestimated the Badger House. Perhaps they were all far sneakier than everyone realized. Small wonder that so many Badgers and Snakes formed friendships. They had different, equally sneaky strategies of accomplishing the same things, and neither House usually included rash, impulsive, hot-headed members, unlike Gryffindor, which had become famous for it.

Lady Aztecatl retrieved her cup of now cold tea and finished it. As she refilled it with fresh, hot liquid, a pleasant herbal scent filled the office air. She made her cup up again with honey and milk, then addressed Dumbledore. "As for you, Albus, I offer my services to the school as Professor of Magical Languages, as I am fluent in Mermish, Elvish, Dragontongue, Gigantus, and Gobbledegook. Hogwarts has never before offered to do so, and I am willing to fill that role. In return I offer my loyalty and protection to those who would oppose the Dark Lord called Voldemort, should he ever return, and I will give my best attempt at identifying the source of, if not successfully breaking, the curse on the Defense Against the Dark Arts position."

Lady Aztecatl briefly looked to Dumbledore, who actually looked interested, if conflicted, as she murmured, "That is the proposition that concerns you, Headmaster." He nodded once, deep in thought. Severus hoped Albus would say yes to her. He wondered if she knew of the old man's meddling, and if that motivated her to give him something of benefit as well, something that would nudge him toward an offer he could not refuse with good reason on top of serving as a means to keep him from interfering with the two of them.

"You have given me much to think about, My Lady," Dumbledore finally replied to her. "And I'm sure Severus has much thinking to do as well. Is that correct, Severus?"

Severus felt a perverse pleasure in the response he gave. "Actually, Albus, I'm inclined to accept each proposition offered to me by Lady Aztecatl."

Albus frowned deeply, though tried to appear diplomatic as he leaned forward over his folded hands. "Don't you need longer to think this over my dear boy?"

Severus's lips twitch as he coolly said, "I'm not sure what there is to think over, Albus. Lady Aztecatl has been more than generous with me and gives me her word that I shall come to no harm. I see no reason to postpone giving her my acceptance."

Albus' frown deepened but he kept his peace in front of Lady Aztecatl. Severus easily slipped into a smirk, or more accurately, a shit-eating grin, though he tried to tamp down on his gloating.

Lady Aztecatl clapped her hands happily. "How wonderful, Severus. Where and when we meet depends on whether Albus hires me to teach here or not." Even as she spoke Severus knew Albus would hire her, assuming she checked out and had the skills and knowledge she claimed. He knew Albus would because he knew that the older wizard would want to try to monitor their activities together. He would also leap at a chance to figure out the curse on the Defense position, and to acquire such a powerful ally against the Dark Lord.

Severus saw it now, in the tilt of her head, her braids pinned up as intricately before; in the way she exuded a look of quiet certainty when Dumbledore busied himself petting Fawkes; the set of her shoulders, sure but not overconfident; the dainty tip upward of her pinky finger. Lady Aztecatl was no fool, and she was getting exactly what she wanted, even if she made it seem like she actually needed Dumbledore to go along with it, even if she placed an advantageous trade in front of each of them. He didn't know her motivations, but he could see that she was someone who knew what she wanted and strived to obtain it, too. He could see that she would be utterly ruthless when she had to be, that she realized her ambitions and manipulated situations to her advantage. Yes, a Slytherin touch indeed. He was certain that had she been sorted, she would be placed in Slytherin House (or, as he had grudgingly realized at the start of the meeting, Hufflepuff; they were quite good at getting what they wanted as well). As Severus observed her, his respect for her rose, not because she was powerful or immortal, but because of how she had ensnared Dumbledore—even now he could see the struggle in Dumbledore as the old man tried to find a way to refuse—and in the way she fought for Severus because she saw worth in him.

Dumbledore exhaled loud and long. "I believe I shall accept your proposition for me as well, Lady Aztecatl. I see no reason at this time to refuse. You are correct in saying that we have been lacking language education, though it has long been considered by Heads of Hogwarts over the years. This is something we can both get behind. And of course I desire to find and disrupt that curse, and to gain valuable allies. I believe it is when, not if, Lord Voldemort shall return. I shudder to think of him courting you for your support, or to think of you making him a similar offer. I am glad to receive your support." Startling himself, Severus realized that he had not even considered that possibility.

Lady Aztecatl's nose wrinkled. "I would never support his side, Headmaster. I am on the side of blood, of life, of balance, of justice. I do not condone his villainy, and I despise tyrants and injustice. Not only do I stand against him, I plan political moves that will ensure fair treatment for all magical beings, not just your kind and mine."

Dumbledore's doubt cleared and he bowed his head. "Then we are similarly inclined."

"Yes, I believe so." She finished her second cup of tea and stood. "I shall begin creating a loose curriculum and moving some of my things to the school, Albus. I'll be in touch about both. Severus, owl me with the date and time when you prefer to begin our meetings, as well as when you would like me to facilitate a meeting with Eleonor and whether your mother will be in attendance."

She inclined her head politely and stepped toward the door. Severus took that as his cue to leave. No way would he be left alone with Albus after this meeting. He stood abruptly and moved to follow her. "I'll escort you, Lady Aztecatl."

"Oh?" She seemed pleased, looking over her shoulder at him, hand on the doorknob. "How nice. Shall I take your arm?"

Severus extended his arm to her blandly. She took it and they departed the office together. As the door closed, she said softly, "Severus, if we will be working together you should call me by my given name, Yolotli."

Severus didn't bother hiding his smirk. "It would be my pleasure, Yolotli." Yes, this would be very good for his own protection, for irritating Albus and for exciting Lucius. He didn't know at that moment which would be more fulfilling.

XXX

"You may not know it, Yolotli, but you have given the Headmaster a run for his money," Severus remarked as they emerged from the spiral staircase descending from the Headmaster's office.

"I take it he is the one who normally gets what he wants and not the other way around," Yolotli replied, grinning in a soft, pleased way.

"I believe he is positively sulking right now," Severus sneered, "though I am sure he did accomplish far more with this meeting than he thought he might." He looked at her as they walked, and she saw more of that cloaked curiosity. "He realizes how valuable you are on our side, even if you are, in his opinion, wasting your time with the likes of me."

Yolotli frowned over at him. "Does he despise you, then? Why would he assist you with your acquittal process if he hates you?"

Severus shook his head. "It is not as simple as that. He does not despise me, but neither does he value me beyond my 'usefulness'. Even then I am expendable to him in the long-run, a pawn to use in playing his game against the Dark Lord."

Yolotli brushed her fingers against his wrist, not letting herself feel offended when he flinched at the unexpected physical contact. "Your worth does not lie in how much and how well you can be used, Severus. Please remember that. I did not choose you for superficial reasons. I can taste your magic from here, and I know of your talent and intelligence because Eleonor follows your work." Severus stopped dead. Yolotli did not immediately realize and had to turn to face him. She cocked her head curiously at him. "You did not know."

Severus, clearly in shock, merely stared at her, and in it she saw a kind of vulnerability that she was sure he was unaware he was showing. "She follows my work?"

"Yes. All she does is talk about how brilliant you are. Every Potions journal article, every newspaper clipping, anything she finds written about you she saves. She's spoken with your old Head of House, Slughorn, and when he raved about your talent she seemed pleased. She's even begged me to mention your name to Nicolas."

Severus seemed utterly stunned, a first for her to see that much emotion on his usually closed off features. The moment passed, however, and confusion replaced it. "Nicolas?"

"Yes—Nicolas Flamel."

He sucked in a startled breath. "She begged you to mention my name to Nicolas Flamel?" A light of recognition appeared in his eyes, which narrowed. "You know Nicolas Flamel, the only known creator of the Philosopher's Stone?"

Yolotli tilted her head, shrugged. "We know each other casually. We worked together on a few projects. He taught me a few things, and I taught him a few things." She waved at the hallway behind her. "Let's keep walking."

It took him a moment to follow her, but when he did he expertly kept up with her. She could practically see his mind working through the information. She watched him in her peripheral. "I meant what I said in the office. I would never work with your Voldemort." She could see Severus studying her in return, and therefore witnessed him flinch at the name.

Giving no other sign of discomfort, he said, "You would have absolute power. There would be no one like Fudge who dared to thoughtlessly mouth off to you."

She crossed her arms behind her back. "I do not want to be a tyrant. Besides, do you really think someone like your Dark Lord would want to share his rule? Even if I wanted to, he would never stop searching for a way to kill me or to become one of my kind."

Severus' head jerked sharply. "Are either of those things possible?"

Yolotli bit her lip, glancing around the empty-looking corridor. Before he could utter one sound she gently but firmly grabbed him by the forearm and towed him inside an empty classroom.

She put up Silencing Wards, then looked into the face of a keenly interested Severus Snape whose sharp, intelligent black eyes bore into her. "This never leaves this room, Severus. I want a Blood Oath on that."

His black eyebrows quirked in a way that clearly meant 'oh really?', as if no one would ever have the audacity to ask him to make one. She did not know, but he had heard of Blood Oaths before, though he had never seen one cast. It was a small bit of Blood Magic that was more commonly known than other, more obscure practices. If he betrayed her then her magic would poison his blood and he would die. Severus shuddered. Sepsis followed by septic shock did not stand out as an appealing way to go.

Yolotli did not back down. "I mean it, Severus. Swear that you will tell no one what I divulge about us."

Severus sneered. "You have already told me more than enough by your reaction. Why you insist on a Blood Oath now—"

Yolotli's power flared in irritation, though she kept it in check. A part of her told her Severus might have noticed given how he stiffened as he sized her up.

"Severus, I will not harm you, but if you want to know the truth you will do this thing for me."

Wordlessly Severus extended his non-dominant hand, palm upward. With her wand she made a shallow gash across his open palm. Yolotli laid her nondominant hand atop his so their hands rested palm-to-palm. His skin felt exactly as she predicted, but she said nothing, smothering the thoughts she had earlier in the week about his touch as she concentrated on his Blood Oath. "Do you, Severus Snape, swear to me by blood that you will not willingly divulge any secrets I share with you today unless you have my consent to share them or I release you from this oath?"

For an instant feeling ridiculously like a groom at a wedding he said, "I do." A faint red glow surrounded their connected hands, dissipating as quickly as it appeared.

Yolotli cleaned and healed his open palm before she spoke, though she did not realize that she held onto it a bit longer than was necessary. Severus noticed but did not know what to make of it. "All right, then, let's get down to business. Yes, and no. There is a way to kill one of us, but it is so extreme and so terrible a sacrifice that no one would do it, not even Lord Voldemort."

"What could it possibly be that it would stay even the Dark Lord's hand?" Severus whispered, filled with dread and slightly horrified already.

Yolotli, who was shorter, peered up at him, up into the midnight pools of his eyes. She could get lost in those eyes if she stared for too long. She quickly looked away, at a blackboard on the far wall.

"I suppose if you think about it, it's technically Sacrificial Magic, or Blood Magic. I won't tell you all the details, but it involves a slaughter, and not a small one. Not hundreds, but thousands, millions, and not just anyone. Spill the blood of a specific group of people, and spill enough of it in a short amount of time and it can be used to overwhelm, maim, or even kill one of us, depending on how far someone is willing to go."

Severus could tell there was something she held back from the explanation, and she could see that he could tell, but neither of them pushed it further. She was, of course, leaving out the part where all the people of one's own nation must die, where an entire nation must be wiped off the map, including any diaspora and their descendants, anyone who remembered what it was like to see or live in or visit that place, anyone who spoke its language. The death was horrible, slow, agonizing. Each Undying One was rooted to their place. If someone obliterated their place and everything associated with it to the point that it could never exist properly again, then they would die, plain and simple, though it might take a century or a few generations. If the nation were restored somehow, if some of their people survived and kept their memory alive and spoke their language and then established a physical place somewhere else, then they could live, but they might be changed from their experience. "It happened before, after the fall of the Holy Roman Empire and Prussia," she finally added. "My cousins were orphaned with the HRE incident." Rome's death showed them both how slowly and how quickly one of their kind could die.

"So you can be killed," Severus said at last. She couldn't decipher his current facial expression.

"Yes, but it is rare, and difficult. Death that way is our only vulnerability. Unless we die we are functionally immortal and mostly invulnerable. Things that would kill you I could recover from, at least with time if not immediately. Once we are born there is no reversing it without committing an incredibly evil act, the very act of which I spoke."

"The mass-murder, yes," Severus agreed quietly. It was still valuable information, though she could see he doubted her assessment that 'even the Dark Lord' would not commit such an atrocity.

"I don't just mean his usual Muggle killing here and there," she insisted with force, "I mean that nothing short of outright genocide could wound us so deeply that we die. And even then, maybe not. At least not immediately." Not until all traces of their essence had been destroyed, anyway.

Severus appeared deep in thought. "The Dark Lord must never know this," Severus murmured at last. "I now appreciate why you insisted I swear a Blood Oath. I do not trust him with this kind of information. I assume no one else knows?"

Yolotli shook her head 'no'. "Only our kind, and none of us would betray the rest, especially not when we can all be hurt or killed the same way."

Severus saw the logic in that: none of them could betray the others without betraying and endangering themselves as well. Anyone with even the slightest sense of self-preservation or common sense would avoid letting the secret out where any Dark Lord or malcontent could hear of it.

Yolotli took down the wards with a single flick of her wand and the door swung open.

"I know you only walked out with me to avoid being cornered by Dumbledore, Severus. I'll leave it up to you whether you actually walk me to the castle gates or simply tell him that you did."

Severus grimaced at the thought of the next time he found himself alone with Albus. "I shall try not to be alone with him for the next year." He once more extended his arm to her. "And I shall go with you so the portraits do not tell him I am actually alone at the moment. In fact, perhaps I should follow your lead and head off for the day. We were to discuss the meeting with you together afterwards, but now I think not. Merlin knows Albus can be a persistent menace when he wants to be."

The classroom door closed to the peal of Severus and Yolotli's combined laughter. In his bedroom that night, Severus would later remember he had asked two questions, and wondered how he had only gotten answers to one.