HP: Those Years Sleeping with the Half-Blood Prince

"However, if the principle is forced binding or partial separation, then theoretically, forcing an already damaged and fragile soul vessel to endure this magic could very well result in..."

"Collapse, or death," Severus continued. "If the mark fails, the caster won't get a useful servant, only a corpse or a useless person, which doesn't align with their purpose of recruiting valuable individuals."

Regulus snapped his eyes open, staring intently at Severus. "You mean..."

"If, before the marking ceremony, your soul is unstable for some reason, and is in a state of magical weakness or damage," Ian said, quickening his pace. He stopped in front of the fireplace, turned around, and his eyes shone brightly in the firelight.

"Then, that person will either postpone the ceremony, or... he might think you don't deserve this mark, at least not now."

"But... but what kind of soul damage could be so severe that they would believe it wouldn't really... destroy me?" Regulus's voice trembled, a mixture of faint hope and deeper fear.

Severus and Ian exchanged a glance.

"Soul soothing agent," Severus said in a low voice, each word uttered clearly and slowly.

"The research we abandoned before." Ian slowly walked back to his seat, sat down, and leaned forward slightly. "Now, it will become evidence of your secret, unfortunate failure, and severe backlash."

"Regulus, because of family pressure and your desire to prove your worth before being accepted, you secretly researched extremely dangerous soul magic in an attempt to create a soul remedy. As a result, you encountered a terrible accident during the experiment, causing irreversible damage to your soul."

He paused, looking at Regulus's pale face.

"The trauma must be real enough to be detected by senior therapists at St. Mungo's, to have Professor Slughorn testify on your behalf that you have been in an abnormal state recently, and even... to allow your parents to witness your pain and weakness firsthand."

"This requires a complete chain of evidence and a flawless performance." Aris conjured a piece of parchment and began writing down the details of the plan. "And most importantly, there must be traces of the accident, as well as... proof of your motivation and ability to research this."

"The motivation is pressure and foolish ambition. There may also be people within the family pushing you, implying that you need to make a contribution," Ian analyzed calmly.

"Abilities... Everyone at the Slughorn Club knows that Severus had previously struggled with this topic. As someone who frequently discussed potions with him, it's perfectly reasonable for you to have received some inspiration or even incomplete notes in private. Nott and Carlo also know that Severus has researched this, so they'll believe it."

"I'll prepare the potion," Severus said. "It will produce magical symptoms and physical pain similar to soul damage that last for several weeks, but it won't cause permanent harm. After the effects wear off, the runes will disappear automatically, and the pain... will be real."

Regulus's lips moved slightly: "Pain...it's alright."

"The accident scene," Kevin finally found his voice, though it was still a little hoarse, "there have to be traces of an explosion, or strong remnants of dark magic, preferably in a rarely used room in the Black mansion, or... the Room of Requirement? That place can simulate any environment."

“The Black House,” Regulus said softly, his fingers digging deep into his palms. “I have a small, abandoned study that used to belong to my grandfather. Almost no one goes there anymore. It makes more sense that something happened there. Kreacher can help with the furnishings; he won’t tell anyone.”

"Time is tight," Aris calculated. "From concocting the potion, familiarizing ourselves with the symptoms, and setting up the scene, to making you fall ill naturally, being discovered by your family, being taken to the hospital, and alerting the school... everything must be meticulously planned and executed without the slightest mistake. Moreover, we must get this news to the right people before the Christmas holidays."

“Professor Slughorn is a breakthrough,” Ian said. “He cares about students with potential, especially those from pure-blood families. If you suddenly fall ill in Potions class and show severe symptoms of soul damage, he will definitely take it very seriously and contact St. Mungo’s and your family. His words carry weight in the pure-blood circle and… well, there.”

"And Lily too," Severus suddenly said.

Several people looked at him.

“Lily helps out in the medical wing, and Madam Pomfrey trusts her. If Regulus is brought to the medical wing after his illness, Lily’s presence will increase the credibility of her testimony, and…” He paused, “she can express concern naturally without arousing suspicion.”

The plan took shape quickly amidst intense discussions, with every detail meticulously considered and every possible contingency taken into account.

Regulus went from initial despair to a faint, desperate flame rekindling in his eyes.

He listened attentively, occasionally offering additional details about the Blake family home or their possible reactions.

"The potion needs several days to prepare, and two of the ingredients are quite troublesome and cannot be obtained by ordinary means."

“I’ll come,” Regulus replied almost immediately. “We have plenty of supplies at home; Kreacher can bring them over.”

"Hmm," Severus responded, "Before that, Regulus, you need to start preparing, become anxious, have insomnia, and occasionally daydream in public, but don't make it too obvious."

"You can subtly let some people see you looking at obscure books about soul magic, or loitering near the restricted section of the library."

"The people Nott and Carlo left behind will take notice," Regulus nodded, some color returning to his face.

"We'll all keep an eye on your surroundings for you." Ian reached out and squeezed Regulus's cold, trembling shoulder tightly. "Remember, from this moment on, you are a pathetic guy crushed by your family's expectations, desperate to prove yourself, but who messed things up. Act out your fear, Regulus, you are genuinely afraid."

Regulus forced a smile, the curve of which was more unsightly than a grimace. "...No need to act."

"Then..." Kevin raised his hand, "What can I do?"

"You're in charge of acting normally." Ian looked at him seriously. "Kevin, you and Aris need to act like everything is normal, continue our blood replenishment improvement project, complain when you need to, and go to Hogsmeade when you need to."

"But if someone, especially someone from Slytherin, asks you about Regulus or us, you should 'casually' mention that they think Regulus has been acting strangely lately, as if he's been messing around with something dangerous, that he looks unwell, and that they warn you not to ask any more questions. Your words will be more believable if they come from you."

Kevin puffed out his chest, his face serious: "Understood! Mission accomplished!"

Regulus looked at them, opened his mouth, and finally only said softly, "Thank you."

"Don't thank me too soon." Ian walked back to his side and patted his tense shoulder. "The road ahead is long and difficult, but at least now we have a path we can see."