This one's a little bit for Hermione, because she has some reasonable questions, and not just about Wanda. Also, co-starring someone we haven't seen much of in a while – Remus! Enjoy.

Oh, and for clarity? This is happening in the couple of days or two, present time, that Harry is on his extended jaunt in the past/on Sakaar. Even if it wasn't a weekend, Harry's proclivity for disappearing is such that only Dumbledore really knows he's gone.

"Professor Lupin?"

Lupin turned and smiled. Not so long ago, walking these halls, being hailed with that title, would have brought a terrible wave of nostalgia, grief, and crushing regret. There were still elements of all three, but the regret was a faded thing, and the grief an accepted and mild taste. Now, he could enjoy it for the sake of it, wandering in his off time. Nominally, it was to keep a finger on the pulse in Hogwarts itself, a check in, but Peter Wisdom, for all that he had forsaken his past, was not ignorant of its importance – nor of it to others.

And, borderline sociopath though he might be, he wasn't entirely heartless.

So, Lupin had wandered and reminisced, largely without regret. Never entirely, of course, but largely.

"Hardly a Professor any more, Hermione," he said. "Technically, it would be Agent Lupin, if we were going to bother with titles."

"Oh, yes, congratulations," Hermione said, pleased but sounding distracted, her hands wringing uneasily. "I'm sorry, I just suppose I think of you as Professor because -"

"Because I was your teacher," Lupin said, sitting down, gesturing at Hermione to take a seat. "And you have a question. If I can answer it, I will. If I can help you, I will."

"Well, I have a couple, actually," Hermione began. "Did... did you know?"

"About your connection to Wanda?" Lupin asked, and at Hermione's nod, shook his head. "No. I deduced that she had been pregnant during the war, and the rough age of any child or children she would have had. However, I had no idea who, what, or where. Now, it is quite obvious in retrospect. Your magic was quite obviously more than a tad chaotic, even when I was teaching you, and I knew Wanda well enough that I should have recognised it and therefore you. And, well. I am sure you are now as tired of being told how much you look like her as Harry is when people say the same of him and James - or Thor, as he was when he was James. However, it is true now, and it was true then."

Hermione looked decidedly sceptical, probably thinking about her formerly protruding teeth and bushy hair as compared to Wanda, a famous beauty who managed to be stunning even when dishevelled. Frankly, Lupin didn't set much store by that. All teenagers had their awkward phases, some more than others, and everyone was their own harshest judge. Especially when they were young.

"All right," she said. "Thank you, I just... a lot of people knew. And they didn't tell me."

"I know," he said simply. "In the interests of full transparency, Wanda confessed that she had a daughter. Not your name, but that she had a daughter. Sirius had confronted her about not taking in Harry, and while she did not name you, your existence came up in that conversation - that she had had you, and had to give you up. Another thing I am sure you have grown tired of hearing."

"I see," she said carefully. "Professor? What can you tell me -" She stopped and swallowed. "What can you tell me about my... about my biological father? His name is John Constantine. I believe that you knew him."

Lupin took a long, slow, and very deep breath. Hermione frowned.

"A lot of people react like that," she grumbled. "Or they look like they want to avoid the subject. There's not much in the books -" This was said as if it was a personal affront. " - he's too recent for that, and not as significant a figure as, well, Harry. There's mention of other Constantines, apparently relatives, but those mentions tend to presuppose a certain degree of knowledge." She grimaced. "And the context isn't usually very pleasant."

"And Harry's fame, his mention in those books, is mostly tied to Voldemort," Lupin said quietly. "Though I rather suspect that newer editions will change that."

He folded his arms and frowned, scrutinising the table, considering what to say. Wondering how, exactly, to be fair.

"You will not find out much about John Constantine in books," he said eventually, meeting her worried gaze. "He's less a man of facts, more one of stories and rumours and reputation, if you can persuade people to talk about him. This isn't out of some superstitious fear, like Voldemort. It is just that there are, frankly, some subjects that wizards do not like to discuss and he is one of them. In all fairness, in many ways Wanda is another, as is Doctor Strange. The latter comparison is more apt. Like Strange, Constantine is someone who lives in the shadows, half out of sight, someone with a justly earned reputation that far outstrips his personal power, a man who of secrets who understands that knowledge is power, and that nothing is more powerful than influence over other people."

He looked Hermione in the eye.

"You asked me if I knew him, and I do. He is an exceptionally dangerous man, even - especially - when he does not intend to be. While I disagree with a great deal of how Wanda has handled her relationship with you, one thing that I absolutely agree with is her decision to keep you well away from him."

"She's keeping him away from me?" Hermione erupted.

"No, I don't believe she is," Lupin said calmly. "I am certain that he knows of you by now. I am also certain that if he intended to visit, he would find a way. There are very few people who could be assured of keeping him out, one way or another. Or I believe there are. John's reputation has taken on a life of its own." He shook his head. "I believe he is avoiding you."

Hermione's expression crumpled. "Why?" she whispered.

Lupin sighed. "Let me go back to the beginning. John went to Hogwarts, like most us, though he was over a decade older than me. Even years after he had left, however, his reputation preceded him. He was a Slytherin, a half-blood who did not pretend to be anything else in a time when anything other than pureblood status - or at least a plausible lie of that, or a willingness to support pureblood superiority - in Slytherin House could be dangerous. Indeed, he was fond of muggle fashions, music, and was that rare thing: a wizard who truly blended in with muggles. Most half-bloods, and muggleborns, tend to drift away from their muggle roots. The nature, and perhaps the tragedy, of our society is that by the end of their Hogwarts years, they have little in common with their non-magical family and friends. As such, there is often an informal expectation that ties will be weakened, if not cut entirely."

"But he was different," Hermione interjected.

"Very much so," Lupin agreed. "John arguably suited Muggle Britain better than Magical Britain, though he was an outsider there, too. As a consequence, he drifted into Wandless circles easily enough. After all, they overlap much more with the Muggle world. More than that, however: he had a natural aptitude for Wandless magic. That, as you may have found, is rare. Of course, he never entirely fit in there, either. Someone else might have been upset about never being able to settle in any community, but John? I sometimes think it suited him, to be able to look at all of us from the outside. It meant that he was in on the joke, so to speak. It also meant that he had both an insider's and an outsider's perspective on things. The insider understands the fine details. The outsider sees the whole of the game. A mind like John's was very good at using that."

He waved a hand.

"Don't mistake me, Hermione, he was not this ruthless manipulator and figure of myth from the start," he said. "He was more like the Weasley Twins; with a darker edge, yes, but those were darker times, and he needed to be sly to survive Hogwarts, let alone the outside world. A knack for acquiring knowledge, and, shall we say, illicit items, earned him some money and a great many favours. That was how I, we, met him while at Hogwarts."

At Hermione's puzzled look, he smiled slightly.

"I am sure you have heard a few stories about my friends and I; me, James – Thor, Sirius… and Peter, of course. We were inveterate troublemakers and pranksters, compulsively curious, and all too often we treated rules as a checklist of things to break," he said, and the smile faded. "We've all changed, since then, of course. Even Sirius, who sometimes seems like he hasn't changed at all and with good reason, is a very different man to the boy that he was."

"So, you bought things from him?" Hermione asked slowly, trying to keep an edge of disapproval out of her voice.

"We were put in contact by friends of friends," Lupin agreed, nodding. "Then yes. We did. The information and resources to become animagi were not easily discovered, and the kind of mischief that my friends and I got up to… well. Sometimes, tips and the voice of experience were helpful, though they almost invariably got us into even more trouble. Despite the age difference, we all became friends quite quickly. Sirius in particular took to him, almost as an older brother. We looked up to him, and of course, he was quite charming. He could talk you into anything - though by the time I really got to know him, that was still mostly just an ill-advised practical joke."

"Was that at Hogwarts?" Hermione asked. "Or... after?"

"After. He was a part of the same organisation that fought Voldemort as I was, along with Sirius, James, Lily, Wanda, Nicholas Fury, and, among others, Doctor Strange - though he was more an adviser and an observer. Dumbledore was our leader. John was as he had been before: a knowledge broker of sorts, someone who did increasingly dodgy deals for information and insight. He was a rogue, but he was our rogue, and a good friend."

Lupin smiled wryly. "Perhaps the best way to sum him up is to say that you could trust him with your life, but you'd be a fool to trust him with your wallet." He snorted. "I did both, during that time. And I only regretted the latter."

"Then what's so bad about him?" Hermione asked, frowning. "What... what did he do?"

"I'm not entirely sure," Lupin said. When Hermione blinked, then looked outraged, he raised a hand. "I am not sure why Wanda specifically did not trust him. With her, it was one specific event, I'm sure of it. I don't know what he did, but it happened very quickly - one moment she trusted him, loved him, the next... I think he was lucky, exceptionally lucky, to survive the experience. And by the look of him, he knew it too. For me, it was a steady development, and it mostly took place after Voldemort's apparent demise. During the war, we were desperate. Voldemort's power was only growing, the days were getting darker, and we knew that we had a highly placed traitor: Peter Pettigrew, as it turned out."

He closed his eyes in regret, thinking on Peter. He had done that many times over the last year or so, after the revelation of what had happened, trying to piece together where it all went wrong, when Peter had made his choice, why he had made it. Sirius, oh so very clear in his opinions, so black and white and clearcut, had summed it up brutally. 'He was a coward. A coward who always wanted to be by the side of the biggest bully in the playground, to pick the winning side and enjoy the reflected glory. Once, that was us. Later, it was Voldemort'.

Normally, Lupin found such summaries to be unkind at best, devoid of nuance. But thinking it over and over, turning each memory dark and treasured alike over in his head, even going through his old journals to spark yet more, he had to reluctantly admit that Sirius was right. It was a funny thing, really. If matters had been different, he wouldn't have hesitated to kill Peter himself. Now, he knew that he was dead.

Thaumaturgic evidence from the World Cup had confirmed that the body that Voldemort was running around in had once been Peter's. Or at least, it was made from what had been Peter's body, which was an important and disturbing distinction. Sirius had got a degree of dark amusement out of it. Lupin himself, however… he found himself remembering less the snivelling traitor, and more the wide-eyed boy who had trailed after them. Wormtail before the fall, as it were. He remembered that boy, and he felt only regret.

"He was someone else I trusted with my life," he said eventually. "Someone that we all did. And we paid for it."

He looked down at his hands. After a few moments, Hermione reached across and, hesitantly, squeezed his hand in sympathy.

"I'm sorry, Professor, if it's too much, I shouldn't have asked," she said.

"No, you have a right to know," Lupin said tiredly. "We were getting picked off one by one, and rarely were the deaths clean. We were all desperate, and John was going to darker and darker places for his information, for his power. When the Wardens came to warn him, he did not take it as a rebuke, but as both a challenge and a source of resentment. He mixed as easily with demons and the fae as he did with us. He became increasingly less concerned about the consequences, and there was always someone else to pay the price. After the war, he was one of those who did not believe that Voldemort had truly died - and he was better placed than most to know."

He sighed.

"As it was, he saw - we all saw - a lot of friends buried or worse, and we all saw a lot of Death Eaters, who we knew were guilty, walk away from justice. After that... John had always cared about not just doing the right thing, but, at least to some degree, doing it the right way. I like to think that he kept his desire to do the right thing, if very grudgingly. But he stopped caring about his methods. He accepted the collateral damage, even the guilt, such as it was, as the price for success. He entered a spiral of self-destruction and never accepted any help to get out of it because ultimately he never wanted it."

He paused, deliberating over his final words.

"John Constantine damages or destroys everything and everyone around him, sooner or later," he said. "No one who enters his orbit emerges unscathed, and he knows it." He looked at Hermione and squeezed her hand. "I think he is avoiding you, Hermione, to answer the unasked question. I think he is doing it not because he doesn't care, but precisely because he does. He's avoiding you for much the same reason that Wanda did: he believes that you are safer without him, that you are better off without him in your life."

"And you agree with him," Hermione managed, damp and sounding betrayed.

Lupin was silent for a long, long moment. "I trusted John once again, years after the war, and a short while before I came to teach at Hogwarts," he said. "I went to him for help, I trusted him, and he used me. What he did..."

His hands clenched into fists briefly.

"When Professor Dumbledore found me before the start of your last school year, it was in the middle of nowhere, my isolation being by design. He had to promise monthly Wolfsbane, brewed by a master, every kind of safeguard imaginable, he even had to plead with me. All so that I would accept a job, an acceptance, that I had dreamed of, one that I would once have jumped at. He had to promise that and more, and still I hesitated. There is a reason for that. And I am afraid, Hermione, that that reason is called John Constantine."

Yeah. I'm not dragging Constantine to retroactively justify Wanda's choices or anything like that. Constantine really does have this kind of rep in canon, and there's a damned good reason for it. Even when he doesn't mean to do it, he has a knack for getting other people to do his dirty work or pay his price, and when he helps… it can be enough that you wished you never asked in the first place. As Remus, unfortunately, found out.