Perhaps to make the story more complete, or perhaps to take the opportunity to berate Sirius, Kreacher's tale began from a very, very long time ago.
"The disgraceful eldest young master left, and everyone was delighted, because he was a bad boy who always upset the mistress. Young Master Regulus was different—he was well-bred, understood what the bloodline and traditions of the Black Family stood for, forever pure."
Sirius frowned, suppressing the urge to interrupt Kreacher, and forced himself to keep listening.
"So that wizards would no longer have to hide, and to restore the glory of pure-blood families, he joined the Dark Lord's organisation at the age of sixteen. So proud, so honoured, the mistress was proud of him too, everything was wonderful..."
"Get to the point!" Sirius finally couldn't hold back, roaring furiously:
"Tell me, what exactly did the Dark Lord make you do!"
Kreacher's sobs grew louder, but he couldn't disobey Sirius's command and had to comply.
"A year after the young master joined the Death Eaters, one day, he suddenly came to Kreacher and said the Dark Lord needed a house-elf."
"So he handed you over to Voldemort?"
"Y-yes."
A flash of disgust crossed Sirius's eyes.
Voldemort took Kreacher to a cave, its lake filled with Inferi, the water enchanted so that only a small boat could reach the centre.
Under Voldemort's coercion, Kreacher drank all the potion. After ensuring his trap was flawless, Voldemort placed a locket inside and added more potion.
"So that's why you ended up like this?"
Sirius asked with a frown, "And what about Regulus? Did he receive many rewards from Voldemort?"
"Young master did not!" Kreacher shrieked. "Young master changed after that—he became troubled, anxious. He took me back to that cave, and then... and then..."
Kreacher broke into uncontrollable wails: "Young master drank all the potion, gave the locket to me, and ordered me never to tell anyone, not even the mistress. He also told me to destroy the locket."
"But Kreacher couldn't do it! Kreacher tried, but couldn't harm the locket!"
"Waaah, Kreacher disobeyed his master's orders! Kreacher disobeyed!"
Kreacher began frantically harming himself, but Sirius no longer had any intention of stopping him.
After hearing Kreacher's account, Sirius's face turned deathly pale. He staggered back two steps.
Lupin pressed his lips together tightly. He had heard Sirius speak of his brother many times before.
In his memory, Regulus had seemed no different from the other Death Eaters—just another madman chasing after Voldemort, preaching pure-blood supremacy.
But now he realised how absurdly wrong he had been.
"He was a true Slytherin, with his own convictions and pursuit of honour," Lupin said solemnly. "Sirius, you had a good brother."
Suddenly, Sirius lunged up like a madman and kicked Kreacher away violently.
"You're lying to me, aren't you! Why was it Regulus who drank the potion?!" He roared like a beast: "Why wasn't it you! You'd already drunk the potion once—you didn't die!"
"Why didn't you drink it again?!"
Kreacher's wails grew louder. "I-I didn't lie to the disgraced Master; it was the master's orders. Kreacher cannot disobey the master's orders."
Seeing Sirius about to strike Kreacher again, Wayne finally spoke.
"Enough. This was Regulus's own choice. Kreacher is just a house-elf, completely incapable of stopping him."
"Perhaps he believed only his death could permanently keep this secret from Voldemort."
"Why did he have to drink that potion himself? Why didn't he tell me?"
Sirius covered his face in anguish, tears streaming between his fingers as broken sobs escaped him. "What have I done..."
Pain, remorse, guilt.
A torrent of emotions assaulted his mind, leaving him breathless with grief.
Sirius realised he'd never truly understood Regulus, misunderstanding him for over a decade. Even moments ago, he'd assumed Regulus had offered Kreacher to Voldemort to curry favour.
Remembering how he'd treated Regulus in the past, calling him a weak fool, Sirius's heart burned with agony. He almost wished he'd been the one to die instead.
Wayne, too, felt deeply moved.
Hogwarts' house system might no longer suit this era.
Originally, the four founders had sought students who embodied qualities they valued.
But over time, certain traits became so strongly associated with each house that people now overlooked other admirable qualities in students.
Regulus was such a case - proud of his pureblood heritage, yet fundamentally kind-hearted.
Moreover, he'd possessed extraordinary wisdom, sacrificing himself to obtain one of Voldemort's Horcruxes.
Though limited by knowledge - unaware Kreacher couldn't destroy the Horcrux - this represented his ultimate act of defiance.
Glory, kindness, wisdom, bravery.
All four founder-prized qualities shone through him.
Yet because of Slytherin's reputation, Sirius had misunderstood his brother all along.
"Kreacher," Wayne said softly, "bring out the locket Regulus entrusted to you."
"I can fulfil his wish - destroy the locket and bring him home."
Home...
Two simple words that pierced Sirius's fragile composure.
"Home! I'll bring the Black family's hero home!" Sirius shook himself violently. "Kreacher!"
"Yes, Master!" Kreacher's hunched posture suddenly straightened.
"Wait, let me examine that locket first." Wayne stopped the two fired-up men.
"Wayne, anything Voldemort values so highly must be important - likely dangerous too," Sirius said gravely. "I suggest giving it to Dumbledore."
"Did Harry tell you?" Wayne asked.
"Tell me what?"
"First year - I beat Voldemort like a dog."
"Second year - I beat Voldemort like a dog again."
"Third year - I..."
"Ahem!" Lupin coughed heavily. "Let me state upfront that I have no connection with Voldemort."
"Of course I know that," Wayne waved his hand dismissively. "I just meant to say that when it comes to dealing with Voldemort, I'm the professional here. Even the Headmaster isn't as specialised as I am."
"Now quickly show me Slytherin's Locket, Kreacher. You haven't lost it, have you?"
"Kreacher has not!"
Kreacher shrieked before disappearing with a crack. When he reappeared, he was clutching a golden locket in his hand. The small locket bore intricate engravings and Salazar Slytherin's name.
As Wayne reached out, Kreacher found himself frozen, forced to watch helplessly as the locket floated into the young man's palm.
He wanted to scream, but Wayne's next words stopped him.
"Right, now we're going to bring Regulus home."
Sirius shook his head resignedly. At this point, he wasn't about to argue with Wayne.
He simply resolved to visit Dumbledore and inform him about everything once they returned.
"I'll come with you," Lupin said.
He now held equal respect for Regulus and wanted to contribute however he could.
"Didn't you hear what Kreacher just said? That boat can only carry one person. Kreacher and I will go alone. You two stay here." Sirius didn't even plan to take Wayne along.
Wayne scoffed. "Sirius, do you really think you can handle the Dark Lord's traps?"
"If you weren't Regulus's brother, Kreacher and I would be more than enough."
"I..." Sirius was left speechless.
Having been thoroughly bested by just one of Wayne's projections, he had no grounds for argument.
After much debate, Sirius finally relented and agreed to let Wayne accompany him.
...
The azure sea churned violently, the air thick with salty spray.
On a massive rock formation, the sharp crack of Apparition suddenly echoed. Kreacher appeared first, followed by Wayne and Sirius.
"Kreacher, lead the way."
"Yes, master."
For once, Kreacher showed Sirius some courtesy as the trio carefully navigated the slippery rock edges towards the looming cliff face. The seawater had polished the stone surfaces to a dangerously smooth finish, forcing them to move with painstaking slowness.
Sirius kept warning Wayne: "I know you're powerful, but the Dark Lord is vicious. You heard about those traps earlier—stay alert and be careful."
"I understand. You'd better watch your own footing first." Wayne grabbed Sirius's arm as he slipped, making the older man flush with embarrassment.
After fifteen minutes of treacherous climbing, they reached the cliff base and entered a stone cave. It was midday during low tide, so they didn't need to swim—instead, walking straight up to a smooth rock wall.
Kreacher pointed excitedly at the thick stone barrier. "Here! Master is inside!"
"Sealed shut?" Sirius frowned. "Is there another way in?"
"Dark Lord's magic!" Kreacher screeched. He pulled a kitchen knife from his pocket and slashed his own arm, letting blood drip onto a particular stone.
Strangely, the blood didn't trickle down the rock, but was absorbed in an unnatural manner.
"A very standard Voldemort spell."
Wayne commented, "He's trying to weaken anyone attempting to break in this way."
Truthfully, his suitcase contained various magical creature bloods - he even had several barrels of dragon blood. A small amount would easily meet the requirement.
But Wayne thought it wouldn't hurt to let Kreacher, this 'loyal servant', feel somewhat involved.
Finally, the stone seemed satiated, suddenly collapsing on both sides to reveal a doorway leading into endless darkness.
"Episkey!"
Wayne pointed at Kreacher's arm, and the wound immediately healed.
"Thank you, noble young master." Kreacher bowed respectfully.
"Enough of that." Wayne waved his hand dismissively and entered first.
Sirius lit his wand, gasping when he saw the scene inside.
Before them lay a bizarre sight. They'd entered at the shore of a vast Black Lake, its surface stretching beyond what the cliff could possibly contain, with no visible ceiling above.
No light sources existed here except for a faint, eerie green glow shimmering at the lake's centre.
"Kreacher, where's Regulus?" Sirius asked urgently.
Kreacher's eyes reddened again: "M-master drank the potion... so many Inferi... so many Inferi dragged him into the lake's depths..."
"Damn it!" Sirius punched the wall angrily. "Then how did you escape? How did you get out?"
Kreacher covered his face in anguish: "Because master ordered Kreacher to go home... Kreacher doesn't know how he returned."
Wayne clicked his tongue.
All according to the master's orders.
"So what now? Are we supposed to search the lake bottom for Regulus?" Sirius said irritably.
Wayne smacked him upside the head in exasperation: "Could you use that pitiful brain of yours? Is this a normal lake?"
"It's a conversion array that transforms corpses into Inferi. A few minutes' soak and you'll be keeping your brother company at the lake bottom forever."
"I've got it!"
Sirius suddenly shouted, then raised his wand high: "Accio Regulus!"
With an explosive bang, a pale, massive figure erupted from the dark lake surface dozens of feet away. Ripples spread as more and more Inferi emerged from the water.
"Repello Inferi!"
Sirius startled himself with the commotion he'd caused, but quickly regained composure to counterattack.
"Petrificus Totalus! Impedimenta! Stupefy!"
Ropes sprang from the ground, binding some Inferi while others fell or were knocked back into the lake.
Sirius dared not use more destructive spells, fearing he might damage Regulus's body.
Wayne sighed and extended his palm, unleashing a powerful shockwave that sent all the Inferi crawling ashore back to the depths of the lake.
He couldn't expect Gryffindors to use their brains at critical moments.
Hmm, that statement included Hermione as well. Her mentality was too poor—she panicked at the slightest trouble, and all her usual cleverness vanished.
Of course, it also included old Dumbledore. The moment he saw the Resurrection Stone, he lost his mind and was nearly done in by Voldemort's scheme.
Seeing Wayne clear the field with a single spell, Sirius finally remembered to plead for help.
He begged, "Wayne, help me. Help me find Regulus's body. I'll give you anything—all the Black Family's gold, all their treasures—it's all yours."
"No need," Wayne shook his head. "Making money is just a hobby, not my profession."
"Besides, isn't Slytherin's Locket my payment already?"
Nameless heroes always moved people. He wasn't some cold-blooded creature who only cared about profit.
Otherwise, he could have just wandered around the Black ancestral home a few times to find the locket. Why bother with all this extra effort?
"Thank you, Wayne," Sirius said gratefully, then asked, "What do you plan to do? Do you need me to do anything?"
The young man rolled up his sleeves and flexed his fingers.
"Nothing at all. Just identify which Inferi is Regulus later."
He grinned. "This is the seaside—my home turf."
Just as Sirius was puzzled, unsure what Wayne meant by that, a thunderous noise echoed from the cavern entrance.
He turned instinctively and witnessed a sight he would never forget for the rest of his life.