The arrival of the Gryffindor Golden Trio felt like a bucket of cold water over the inhabitants of Grimmauld Place. While before they could avoid thinking about the outside world by focusing on the immediate present, the news brought by the three friends had reminded everyone of the very real danger that awaited them in the streets. Daphne started to focus on theoretical defensive magic, hoping to translate it to practice if she researched enough. The two Malfoys disappeared a couple hours a day to what the blonde girl suspected was a bit darker that what was socially accepted in the house. She even heard her mother asking her father to teach her how to cast a basic shield.
As for the newcomers, Daphne was conflicted. The three spent a lot of time in the master bedroom, claimed by Pot- Harry! When they came out, the three had some kind of metaphorical bubble around them, and they often shut up whenever someone entered the room they were in. Greengrasses and Malfoys understood the need of secrecy however, so that didn't bother them as much as it could have, given how rude that behaviour was.
However, if Daphne had one talent, was her ability to understand and process information. She may not be a genius like Granger or a natural talent to magic like Harry or her own uncle, but she was able to comprehend the information she had at hand. Combined with the observational skills her father had drilled on her since she could pronounce the word "politics", she quickly caught up on something weird.
Despite two of them still treating the rest of the house with caution, Weasley was not particularly rude. He could maintain a polite conversation, and Astoria had managed to talk with him almost an hour about Quidditch during a peculiar breakfast. Granger, despite wearing her emotions on her sleeves just like the two boys, (and therefore failing miserably at subtlety), had engaged both Gareth and Daphne in small talk in the Black library. The Slytherin had been surprised to notice that the immense amount of knowledge the brown-haired girl had wasn't limited to academic knowledge when she and her uncle discussed the deplorable state of magical literature.
Harry was, by far, the friendlier of the three. He talked with all the inhabitants of the house, and he and Draco usually chatted a couple minutes before meals. However, and overall, the raven-haired listened. She could talk about magical traditions and runes, and he would only talk when he had a question. He listened to her father about lordships, Lady Malfoy about House of Black and its history, and her uncle about the Ministry and the Department of Mysteries, the latter talks usually joined by a curious Granger.
That in itself wasn't weird. What caught Daphne's attention were the mood swings. The grumpy Weasley turned into a prat, sneering and snaping to everyone, even his friends, over the stupidest things. Granger would turn jumpy and distracted, closing books shut and sending death glares to everyone who made even the slightest noise. Harry looked distracted and had a permanent annoyed scowl on his face.
Now, the blonde knew that people could have mood swings, extremely so when subjected to the amounts of pressure the three of them had. However, the changes were cyclical. Two days, then switch. Two days Weasley, two days Granger, two days Harry. Same duration, same order.
It took her a couple weeks for her to notice the changes and another one the convince herself of the pattern. Emotional changes, likely generated by an external force, reeked of dark magic, and Daphne knew exactly what to do when she met with dark magic she didn't knew.
Almost a month after the arrival, she went to her uncle. And three days after that, unspeakable Gareth Greengrass went to talk to them.
As always, the three stopped talking as soon as somebody else entered the room, this time the kitchen. The younger Greengrass brother felt three pairs of eyes following his way to a chair.
"I have respected your need for privacy" Started the elder man. Communication had never been his strength, so he resorted to a reasonably formal start. "However, I can't allow something as dangerous as an Horcrux so close to my brother and his family"
The reaction was explosive, the redhaired boy jumping to his feet wand at hand, and the girl narrowed her eyes in suspicion. Even Mr. Potter was eyeing him warily, his hand leaning towards his pocket. "Why do you know about Horcruxes?" asked the latter, with a surprisingly calm voice masking his alarm.
Despite himself, his pride overcame his caution. "Kids, I AM an unspeakable. I know about magic more complex, weirder, and more dangerous that 95% of Britain believe it exists. Even about some knowledge that should have been forgotten long ago" Since neither answered, he kept going. "It took a couple of charms, sure, but only a Horcrux responds that way to a darkness detector, soul magic detector and focus tracker charms. So, I have to ask now why you think a horcrux is the solution for whatever conundrum you face now"
A bit silly really, considering said conundrum was looming over the lives of everyone in the house. However, the phrasing seemed to work, since the three looked at him with huge offend expressions in their faces.
"We didn't make it!" sputtered Ron, backed up by the offended nods of the other two.
Gareth quirked an eyebrow. "Why haven't you destroyed it then?"
Hermione huffed. "If we could, we would have done it already. We don't have basilisk venom, and I won't summon Fiendfyre inside a house. Not only I am unsure if I could generate enough, but the risks of losing control over it-"
The man was quite familiar with nervous verbal vomit, common in a department with many socially-awkward prodigies, so he interrupted the girl with ease. "Both good options, but the killing curse is just as effective to destroy these abominations"
The disgusted expressions in the young trio made Gareth decide to check on Daphne and Astoria's Defence education. The complaint only solidifying said decision. "We won't use an unforgivable. It's wrong, and illegal, and we probably will get tracked-" sentenced Hermione.
"The unforgivables are only punished when used against another human being. And besides, the Minister has no way of tracking the use of a specific spell, less so inside wards this strong."
The three fell in silence. The raven-haired young man looking at Gareth straight to the eyes, thinking. "Are you sure?"
The unspeakable nodded.
"Harry, I-"
"Do you have a better idea Hermione?"
The tone of the question made the man analyse Harry's face, now realizing how tired he looked. Everybody in the house was stressed, and likely sleeping less than they should, but the young man in front of him was specially wore out by the situation. It was like he had the weight of the whole world upon him.
Hermione huffed before searching inside her blouse, placing a rather big locket in the kitchen table. Gareth casted the same detection spells he mentioned early, confirming his suspicions. The wretched thing was in front of them.
"Get ready to dodge or shield" he said. "We don't know how it will react"
Two whispered Protegos were heard, and he was surprised to see Harry half covering him with his shield. Summoning all his internal turmoil, his despise for the beast in the shape of a man that terrorized his beloved country, the despicable animals who threatened his nieces, he casted.
"Avada Kedavra"
The green magic bolt bounced off the locket, ricocheting to a cabinet door, pulverizing it with a loud crystalware crash. Despite his surprise, a background part of his brain congratulated himself on casting privacy charms.
The four got closer to the table, examining the locket. There was a small dent close to the centre, but otherwise it looked intact. Gareth casted once again the detection spells, founding the same result.
"I thought you said it would work." deadpanned Ron, more confused that angry.
"It should have" answered the unspeakable. "This thing must have heavy superficial protections. Let's try to open it"
"We can't" counteracted Hermione "We already tried to, but it doesn't budge to any physical pressure or any charms I know"
While Gareth and Hermione reviewed the used spells, Harry closely examined the artefact. The small indentation was bruising the snake's body, and while the locket still gave him the same uncomfortable feeling, the eyes of the snake were slightly different. Almost… fearful.
"No" he said, making the scholars jump. "We haven't tried everything"
The three looked at him puzzled, before Ron exclaimed excitedly. "Of course! Parseltongue!"
Filling for later the knowledge that, apparently, Harry Potter of all people was a parselmouth, Gareth nodded to the raven-haired man. It was decided that Harry would open the locket and then dodge out of the way, with Gareth casting the curse as soon as he was behind Ron´s shield. Hermione would cover for the elder man.
However, this tactic gave the wretched creation a couple of precious seconds, and it used them in full. As soon as Harry opened the locket, a dark mist poured out of it, clouding their vision and talking directly to them.
"Yet another group you invade, Gareth Greengrass" whispered the mist. "When will you realize that your brother's family only accept you out of pity"
Right next to him, Hermione heard the entity. "You better keep reading little beaver. They only tolerate you because you spend more time with books than with people, making yourself useful"
The two froze, plans forgotten as the mist skipped Ron and targeted Harry. "How many more people have to die, because you can't face your destiny like a man?"
Ron's pride broke his own stupor, as he yelled challenging to the mist. "Nothing to say to me coward?" The voice focused on him. "Undesired by your family, undesired by your friends. You are nothing to me Ronald Weasley"
Thankfully, Ron's yell broke the others three shock. The unspeakable focused on the locket, while Hermione, in an inspirating choice blew the mist between her and Gareth with a precise Ventus. The green bolt of the killing curse flew throw the gap, hitting the locket in the middle and causing the mist to contract in itself with a disgustingly loud screeching noise before imploding, leaving the four of them dishevelled in the middle of the kitchen.
Gareth moved slowly to check the locket, while the golden trio looked at each other. They were pale, Hermione with pursed lips and hugging herself with one arm, Ron with a grey face and a nauseous expression, while Harry seemed unfocused, eyes lost in the distance.
The older man was apparently satisfied with the results, as the spells came negative for the first time. With a tired expression, he sat heavily in one of the chairs, before summoning a bottle of firewhisky and 4 vases from other cabinet, not the one destroyed by the first curse. The unspeakable internally shuddered as he considered how effective that defence could have been with only one target to attack emotionally.
As he poured himself one, he acknowledged the doubtful expression on Hermione's face and motioned for them to seat. "I just thought we could use one. You don't have to."
Ron served them a small portion each. As both him and Harry coughed at their first taste, Gareth barked a laugh before commenting. "If its your first time drinking it, maybe a bit of water could help"
Despite she herself not coughing, Hermione poured a bit of water for the three. In silent agreement, the four decided not to ever talk about what they heard in those moments. After a moment of silent contemplation, the unspeakable broke the silence. "I take that was the Dark Lord horcrux"
The three gave him a small nod, causing him to chuckle. "Well, that certainly explains his miraculous survival all those years ago. Without this abomination, victory now seems possible"
The trio looked at each other, concern in their faces before Harry said slowly. "This wasn't the only one. We know he has others."
Gareth stared at them for several seconds before calling the bottle back to him and pouring another vase. After downing it in one gulp, the man looked at the young ones, bewildered. "How many more?"
The trio looked at each other again, unsure of whether or not answer that question. At that, the unspeakable sighed. "I understand that you need secrecy. In case of these artifacts, I encourage said secrecy" The man stopped to clean his glasses, tiredly. "You don't need to do it alone kids. You don't have to tell every detail for people to help you out. Manage the information if you must, but don't believe you have to tackle this monster by yourselves" At that he left the kitchen, nursing the bottle of liquor towards his room. It had been an exhausting evening.
The night found Harry Potter standing in front of one of the multiple Grimmauld place rooms, hesitant to knock. The discussion had extended the entire afternoon, with the three establishing clear borders on what they were allowed to reveal and to whom. Ron was the least convinced, with Harry being the most and Hermione being the worst middle point ever, only intervening when she disagreed with both. Fortunately, they managed to arrive to an agreement.
Gathering valour, Harry knocked on the door, it opening in a moment, revealing Narcisa Malfoys silhouette. The older woman smiled and asked playfully "I will assume Draco hasn't taught you about this precise interaction, has he?"
At the young man confusion, she elaborated. "If the lord of the house arrives late at night at a woman's chambers, and she receives him, it is assumed that the following events will be of a more… private nature"
It took a couple of seconds for Harry's brain to process the new information, but when it did, he turned into a rather pretty shade of red, almost shining in the barely existing light. "I didn't- It's not- I mean I-"
The elder woman rolled her eyes and spoke in a tone that showed that Lady Narcissa Malfoy wasn't only a mask. "Of course I knew that weren't your intentions Lord Black. I would not have answer if I suspected otherwise. Enter, before this looks worse that what it really is."
Harry entered the room sheepishly, before being guided to a small chair in front of a mirror, where he confirmed his significant blush. Narcissa sat primly in her bed, carefully putting distance between them. "Now, before you pass out, how can I help you?"
The reality went down on him once again, his determination coming back with a vengeance. Looking at the woman straight in her eyes, Harry asked with a surprising amount of security in his voice.
"I need to know everything you knew about your husbands book club. And about an old diary he had a couple years ago."
AN1: I started writing this before Wizards Unite revealed Gareth Greengrass as Astoria's (and Daphne's) father. However, given that Daphne is more of a fanon product, I will stick with Cyrus as her father (also a fanon cliché) with Gareth being a plot-convenient unspeakable uncle.
AN2: Can the killing curse destroy a Horcrux? I don't know. The unspeakable says it can. I believe him.