Hey, everyone! There is an AN at the bottom of this chapter - one that's actually semi-plot-relevant and not just my rambling to you all - that details my head-canon about Lily Potter's sacrifice. Please read both that and Heindoffer's (slightly revised) explanation about Horcrux creation - I'd love to hear your thoughts on it.

Originally posted: 5 Jul 2021? (I don't remember)

Previous updates: 14 Oct 2021, 5 Dec 2021, 2 Feb 2022, 17 Mar 2022

Most recent update: 17 Apr 2022

When Philips returned with another loud crack, he wasn't alone. A woman wearing a Florence Nightingale-esque nurse's outfit found her footing first; the unknown gentleman shuddered uncomfortably as he saw their landing area. His clothes were similar to Philips', Heather's, and even… Cedric's outfits, now that Tony thought about it. He really did hate the Spanish Inquisition – he never expected it.

No one, least of all Tony, anticipated Heather jumping up, seemingly fully alert, and pushing said man behind her protectively. Even the teen in question blinked in surprise when a sword appeared in her hand; her wicked cackle kept the newcomers even further away than did her clumsy handling of the weapon. "What the hell is this," she snarled, her voice rough with sleep, "the Norman Invasion without ships? Get out."

Someone whom he'd only met earlier that day, a tiny slip of a girl at that, trying to defend him? Color him intrigued.

"Heather," Philips tried to reason with her, "Tony asked–"

"That's Miss Potter to you, Auror Philips," she hissed back. "Mr Stark, did you give permission for these two people to enter your house?"

The engineer tore his eyes from the sword, which was, inexplicably, shooting golden sparks from the blade. He temporarily gave up on his dear old friend, logic. "Um, no? Philips just said he'd be back and left. Never said anything about party crashers." Philips shot him a disappointed look before returning his attention to the weapon swinging in his direction.

She was forcing them onto the back foot, he realized, while 85% asleep and inexpertly wielding a sword that looked like it was twice her size and weight. Forget intrigued – color him impressed. Even Rhodey wouldn't be able to manage that.

"Miss Potter," the woman spoke up, her empty hands on full display as she raised them peacefully, "I am Healer Michelle White. I work on the magical side of Seneca Hope Hospital, and I'm the Healer dispatched whenever the DMLE calls, if possible."

Heather clearly didn't want to be placated, if the amount of sparks leaving the sword now was any indication. "That's nice. Get out."

"I asked Healer White and Curse Breaker Heindoffer to come," Philips said quickly, his pitch beginning to rise in his otherwise well-hidden panic. "Tony – Mr Stark asked me to check you over; you were shaking, and he was worried about the possible nerve damage you had mentioned. So I ran some quick diagnostic scans, and realized I was out of my depth."

"I. Don't. Care," Heather snapped. Disneyland's fireworks displays had nothing on what the righteously enraged girl was unleashing through her trusty blade. Tony just had to figure out how to mass-produce the effect so he could market it and make her a mint. "This is Tony's home. He has the right to allow or deny anyone entrance. Wizards seem to think that, just because Muggles don't have wards, they can come and go from their buildings as they please, since they've got the handy-dandy Memory Charm. You two are trespassing. And you, Auror Philips, have overstayed your welcome."

Holy fuck, Rhodey was gonna love this kid. She wouldn't be able to drag him away from assholes, or hold him upright if (all right, when) he over-indulged while dealing with them, but she definitely could, and likely would, tear strips off of the idiots when they inevitably crossed the arbitrary line. And kick them in the metaphoric gonads. Possibly even literally kick them there, too. (He couldn't wait to bring her to an event.)

When the three officials looked at him, he shrugged. "She's right, about all of it. Maybe if you'd knocked and waited for permission to enter, like you did earlier, you'd have a leg to stand on."

Heindoffer, having watched and listened without interceding, took hold of both his compatriots – the soulmates were viciously pleased to see the vice-like grip on Philips' ear – and dragged them out the front door. About fifteen seconds after it latched behind them, someone knocked.

"Gemstone," Tony grinned nervously, "why don't you leave the sword in front of the TV for now? If they deserve skewering, you can still easily get to it. I won't even stop you."

"It's venomous," she slurred sleepily, lowering it as the sparks ceased. "I don't need human kebabs; I just need to cut them. It's why I'm not too worried about learning to use it. I already know the most important part: the sharp and pointy bits go in the other guy."

He blinked. "Well, you're not wrong, but… please, honeybee. Swords do not make good walking sticks, especially when it's – how is a sword venomous?" Yep, logic had taken a vacation to Timbuktu and destroyed its Stark Phone on the way. "Never mind. Right now, I'm more worried about you cutting yourself by accident."

"I'm a moon," she yawned, putting the blade where he suggested with a level of unease that he couldn't even fault.

"You're… immune? To the venom," he clarified, and she nodded. "That's… well, that's something. You and Philips are kinda making me reevaluate my whole worldview, so I'm slightly lost for words. Don't get used to it." The knock sounded again. "I'm coming – hold your horses! Sheesh!" When he opened the door, he was completely unsurprised to find the three magicals they'd kicked out.

"I apologize for our earlier, unauthorized arrival in your home, Mr Stark," Heindoffer groveled. "We have protections on our homes and businesses to prevent such occurrences, and… well, you don't need to hear me ramble about that. I'm Billy Heindoffer, curse breaker extraordinaire. I work for Gringotts, but I owe Johnny here a favor or twenty." Heather poked her head around Tony and glared as angrily as she could manage at the auror, flinching violently when the engineer wrapped his arm around her. Her soulmate managed to shove his anger down before the teen could sense it; White noticed her reaction and narrowed her eyes. "I know the scans were done without your personal consent, Miss Potter, but I would have assumed, as Auror Philips did, that Mr Stark's request implied permission."

She stared at him for a long moment as her expression slowly morphed into something nearing neutral. "You're a Muggleborn, aren't you?"

Heindoffer blinked. "I assure you that being No-Maj-Born, as we say in America, doesn't hinder me in my line of work–"

"It's not that," she shook her head. "You get what the issue is. They don't, even after I spelled it out for them."

"First time my blood status has ever worked in my favor," he snorted. "May we come in? If Philips's overview is right, I'm amazed you're conscious, let alone standing."

Heather and Tony shared a look. "Your house, your call."

When, an instant later, she leaned into his hold, with him supporting most of her slight weight, he made his decision. "As long as you can explain why the hell he brought you," he allowed, letting the three in. "What's wrong," he sneered at White and Philips, "cat got your tongues?"

"No, actually," Heindoffer answered. "I hexed them to silence so they don't screw this up any further. I saw a coffee table in the lounge – mind if I spread out my gear on it?"

"That's fine," he agreed, leading the group back to the living room. He caught Heather as she tripped over air. "All right, little gem?"

"I'm knackered," she groaned with another yawn. "I don't care what your clocks say; it's, like, 4AM to me. Yesterday went to pot so fast. I didn't sleep well this past week from nerves. I passed 'exhausted' on Tuesday, maybe even Monday. I just wanna crash, but… nightmares…"

He tugged her down onto the couch with him, his arm staying around her shoulder as she instinctively snuggled into his hold. "Do you want to stay awake – hear what's going on and make your own choices? Or would you rather catch some z's and deal with whatever I decide on your behalf?"

"Awake," she immediately replied. "But I want you here, no matter what."

He kissed the top of her head. "Done. I'll make sure you don't doze off again, kitten. So, Heindoffer, what's going on?"

"First, call me Billy, if only 'cause it's easier to say," the curse breaker mocked himself. "Second, well, John didn't tell me everything, for a couple of reasons. I don't need to know most of the medical crap, of course; and when Dark Magic is involved, it's actually S.O.P. to not give any more info than that, both for independent confirmation, and because, a lot of times, healers and aurors can't identify it further." Philips, still silenced, nodded and held up two fingers.

Heather froze, her terror so strong that Tony could taste it. (It tasted like dragon fruit. Ugh.) "Dark Magic?" she whispered.

"Without us getting too bogged down with details," the engineer cut in, grave despite the semi-sarcastic phrasing, "can I assume that Dark Magic – and yes, I can hear the capitalization – is the bad hoodoo?"

The girl nodded. "Most magic is neutral; classification is based on intent. I can levitate a person off their hospital bed to change their sheets – that's grey. I can levitate a person to rescue them from a burning building – that's light. I can levitate a person over that cliff for Wile E. Coyote impressions – that's dark."

"I can think of one spell that has no… evil applications," Heindoffer added. "The Patronus. It's fueled–"

"Happy thoughts, faith, trust, and pixie dust," Tony cut to the chase, to the amusement of the other adults. "Tink, here, gave me the lecture when she showed me hers."

"Impressive," Heindoffer whistled. "Not everyone can cast it – it's a damn tricky spell, which makes me wonder why, how, and when you learned it, especially so young." She met his eyes unwaveringly, unbowed by his fishing expedition. "Can't blame me for trying. Anyway, the other side of the coin – Dark Magic has no application except to cause harm. Easiest example is the Cruciatus Curse. Its only use is torture, causing absolute agony by making each and every individual nerve in the body think it's being stabbed, crushed, electrocuted, frozen, and set on fire simultaneously. Cumulative exposure of more than five minutes in half an hour leads to temporary nerve damage–" Turned away from the others, as he was, to set up his tools, he failed to notice Heather's cringe, or the look the other three adults shared that promised retribution. "–and more than 20 minutes in an hour leaves you brain dead."

"One of my classmates," Heather mumbled, "his parents were tortured into insanity with it. Their minds broke." No one mentioned the tremor in her voice.

Tony held her closer. After a minute of silence, he nodded. "Okay, got the basics. How does that bring us to the here and now?"

"Johnny said his scans picked up some Dark Magic attached to you, Miss Potter," the curse breaker restated. "May I do my own scans, to see what's what?"

"Does Tony have to leave?" she whispered desperately, her eyes wide in fear. For the first time that day, aside from his initial impression, the man in question was struck by just how young she really was.

"I wasn't planning on asking him to," Heindoffer replied, "but, for safety reasons, he can't be touching you."

Tony smiled encouragingly, not knowing what words would help her at that moment. She gulped, squared her shoulders, and moved three feet to her right. "Go ahead," she muttered, closing her eyes when he raised his wand. Tony vaguely recognized the first series of movements from Philips's earlier casting; but everything after the first pause was new to him, and deepened Heindoffer's frown into a scowl. "Are you done yet?" she asked nervously when he'd done nothing for a full minute.

"Couple more scans," he responded, shaking off his distraction. He ran whatever tests he still required and wrapped up quickly for her sake. "All set, Miss Potter." She practically flew back to Tony's side. "Well, I know what we're up against," he said to the engineer. "Do you have anything, preferably with some heft to it – solid, not hollow – that you aren't sentimentally attached to? That you'd be willing to donate to the cause of saving Heather?"

"Well, that sounds…" Tony hesitated. "I'm not sure if it sounds ominous, or like you wanna demolish my house. Which is still ominous. I got just the thing. Little gem, are you coming or staying?" Silently, she stood, taking his hand when he offered it to her.

He led her down the stairs to his workshop. The lights turned on automatically. "Welcome to my favorite area of the house," he brought her in with a wide smile, enjoying her look of wonder. "You're welcome here anytime. Stay here for a sec. I left the place a mess last night, and I don't think you need to get hurt."

Walking through the clutter, he grabbed a hunk of rock that had been acting as a paperweight on a table in the middle of the room and showed it to her proudly. "My very first weapon," he confided, tossing it to her gently. "First time I was kidnapped, I was six. We were outside, no idea why, and I managed to get away from the bad guy watching me. He chased me; I tripped, grabbed the first biggish, heavyish thing I could pick up, and threw it at him. Aimed for his head. Actually connected below the belt. Pretty sure it worked out better that way. Aunt Peggy was impressed when she found me a minute later."

"Why not your mum or dad?" she couldn't stop herself from asking.

He flinched imperceptibly. "Aunt Peggy was the best one for the job."

She let the topic die, as he wanted, and passed the stone back. "That sounds sentimental," she murmured teasingly instead.

Snorting, he tangled his fingers in her hair. When he tugged gently, she purred in contentment. "I've never been accused of that before, sentimentality. Billy the Kid up there needs it to get rid of the Dark Magic, somehow. This rock has already protected me, gattina; let it protect you, too."

"Okay," she agreed softly as they climbed the stairs.

Without a second thought, Tony threw the rock to Heindoffer. "Will that work? Or would you prefer something metal?"

"This is perfect," Heindoffer said, inspecting the object. "So, this is a good news, bad news, good news situation. The good news is, it's not a Horcrux."

Sitting back down on the sofa, the teen blinked owlishly. "That sounds... suitably evil," she said for everyone else, who, from what her quick glance around the den showed her, understood the word as well as she did. "I'd probably feel more relieved if I knew what the bloody hell a Horcrux is."

"It's a flawed method of achieving something approaching immortality," the curse breaker stated bluntly. "It requires a Dark, nearly Black, ritual on the object which will be housing the soul fragment. The creator must kill an innocent, which rends the soul in twain – and if you're wondering, that's the exact phrasing Dugbog used when I first encountered one on my third day in Egypt. One piece stays with the creator – the main soul piece, if you will; the other is then bound to the prepared object, now called a Horcrux. If the creator dies naturally, the soul piece in the Horcrux moves on too, though the item still requires cleansing because of the earlier preparatory, evil ritual. But if the creator dies by unnatural means – is killed, in other words – the primary soul fragment will remain bound to this plane of existence, allowing for, if there is anyone to complete it, a resurrection of sorts. In order to remove the soul fragment from existence, the container – the Horcrux – must be destroyed irreparably. And all Horcruxes made by the person must be destroyed in order for said person to truly die. I've never seen a Horcrux without at least one brother."

"So, you're saying it's like Sauron's one ring," Tony related it to one of his favorite books, "and we have to find Mount Doom to destroy any others that pop up?"

Heindoffer shrugged. "While not exactly accurate, it's not the worst analogy I've ever heard. And it would probably be effective. I'll see if we can find a volcano next time." He rubbed his neck. "So again, it's good news – the Dark Magic attached to you is not a Horcrux. Bad news: it's a soul leech."

"A… what now?" White asked, as disturbed as the others. Tony pulled Heather closer for their mutual comfort, mindful that she still had injuries that hadn't been identified; her fingers clenched anxiously around his Black Sabbath t-shirt.

"A soul leech," Heindoffer obligingly repeated. "Functionally identical to a Horcrux, but created accidentally. Usually happens when there is some kind of… misunderstanding of the word 'innocent'. Most of the sickos who create Horcruxes think it means either a child or someone whose death will benefit them but has done nothing directly against them; the actual requirement is someone who, at that moment, isn't fighting them or their impending death, occasionally to the point of actively campaigning for it. All circumstances of soul leeches I've come across have also occured when the person has become insane, thinking these things are a good back-up plan, because they've gone past the… recommended number of fragments, so to speak. My best guess on who, in this case, is Voldemort."

"Who?" Tony demanded, completely bewildered, as Heather sat up in alarm.

"He killed my parents," she explained succinctly, deciding to elaborate at another time. "Would having these cross-thingies make someone seem inhuman?"

"I've never had the misfortune of meeting a living person who's made one," he said honestly, considering the question, "but probably. I mean, removing part of the soul is almost like lobotomizing oneself."

"You said that there was a way to… resurrect someone who made a crud-doodad and subsequently got… semi-killed or whatever you want to call it?" Heather swallowed nervously.

No one was comfortable with the topic, but Heindoffer cleared his throat. "Yeah. The most-referenced, and supposedly safest, re-embodiment ritual requires a potion with ingredients including, but not limited to, bone of the father–"

"Bone of the father, unknowingly given," she intoned without inflection, her eyes focused solely on whatever memory was playing in her mind, "you will renew your son. Flesh of the servant, willingly given, you will revive your master. Blood of the enemy–" The girl's voice fell to a pained whisper as she finished, "–forcibly taken, you will resurrect your foe." She gripped the inside of her right elbow reflexively, as if to stop non-existent bleeding from a freshly healed cut Tony hadn't noticed before.

Several seconds later, the curse breaker picked his jaw up from the floor. "How the hell do you know that, little girl?"

She flinched at the address. "Not because I'm a Dark Lady in training, you gormless dunderhead," she snarled. Wow, she needed to stop channeling Snape. But then again, he did have an unmatched lexicon of insults that she could easily borrow from. Hmm, what a conundrum… "I was the enemy. It was my blood he stole, just a few hours ago. What's the other good news?"

Unlike Heather, Heindoffer needed a moment to get back on track. "Well, any living creature that has been made a Horcrux must be killed in order to destroy the abomination. But a soul leech is much easier to deal with, for a given definition of 'easy'; it's stuck to you, not bound. I can remove it and store it in the rock. I can then use this soul fragment to remotely link and destroy the entire soul, including the piece in the newly-recreated body."

"How painful will it be for me?" the teen pressed. "How long will it take? Can you do it now?"

"What's the most painful thing you've ever experienced?" he pondered.

She didn't even need to think. "Cruciatus Curse. Twice. Earlier today – yesterday – whatever. Time's a bit screwy on me right now."

"Shit," White and Philips cursed in tandem. Tony agreed, but his voice refused to work; it was one thing to suspect that she had been tortured, quite another to have her confirm it so impassively.

"In comparison," Heindoffer pursed his lips, "about a four out of ten. Takes about 20 minutes; and honestly, since I realized what's what, I've just been waiting for you to say that. It'll be best if you lie on the floor. She's likely to thrash around a lot," he said to Tony. "I need you to hold her arms and legs down."

"Why not just put her in a full-body bind?" Philips asked. "I could do that."

"Do I tell you how to do your job, John?" Heindoffer bit out. "I don't want to kill her, that's why not. This ritual – all chanting, you knucklehead; don't get your panties in a twist – doesn't react well to active magic, especially if it's being done by someone other than the one performing the damn thing." Looking to Heather, who'd done as he'd suggested, he instructed her more pleasantly, "You need to remain conscious as long as you can. You'll probably pass out as soon as it's out of you, so I'd like to get your permission now to re-examine you afterwards, to make sure I didn't miss anything by focusing on the greater evil."

"That's fine," she agreed, exhausted, "as long as Tony stays."

"I'd like to examine you as well," White interjected quickly, "with your soulmate there, of course. I can take care of any minor damage while you're out, and we can discuss in-depth healing and a longer-term potion regimen in the morning."

Heather nodded her acceptance of the plan, followed by Tony, who trusted the magicals with her less than he trusted DUM-E's smoothies to be fit for human consumption. "Great, we're all agreed – huzzah!" Heindoffer snarked. "I hate dealing with malevolent souls, so can we get this over with?"

So, to me, this makes the rebounding Killing Curse more sensical. I've seen it said, probably on this site somewhere, that Lily wouldn't have been the only mother to beg for her child(ren)'s survival, and I agree with that. But we know she actively begged Voldemort to "take [her] instead." I think (and the canon for this story is) that Lily Potter, in her rush to, as James (in this story) said, "take Heather and run," accidentally left her wand in the living room, and thus was the only mother Voldemort directly faced who had nothing with her with which to protect her offspring except her body.