The moment Sirius stepped out of the cave, he was met with the gaping maw of the Black Dread, its flames fueled by rage, ready to immolate him. However, unlike before, Sirius was not afflicted by magical exhaustion, so there was no need for him to flee.
Swiftly flicking his wand, he conjured his most powerful shield, fortifying himself just in time as the searing hot dragon fire crashed against it. The shield held strong, protecting Sirius until the dragon's breath waned, both literally and figuratively. Looking up at the creature with an infuriating smirk, Sirius taunted in an arrogant tone, "Your puny flames didn't work the first time, so what made you think they would do anything to me this time, you slimy lizard!"
It seems Sirius didn't need to learn parseltongue to convey his message, as the dragon's eyes immediately turned reddish, roaring in fury and launching itself at the spot where Sirius had been standing just moments ago. With a loud snap, the dragon's jaws closed with alarming speed.
However, Sirius had come prepared, assuming his half-grim form prior to facing the dragon. His heightened senses and augmented strength enabled him to effortlessly dodge the ancient beast's lunge. Waste no time, he taunted once again, "Are you losing your eyesight in your old age, you little snake?"
By this point, the Black Dread had succumbed to mindless rage, allowing Sirius to easily lead it away from the cave towards his desired location. During the Basilisk and the dragon's attempts to breach the cave, they had wreaked havoc on the surrounding trees and rocks, inadvertently creating a makeshift clearing. This spared Sirius from worrying about excessive obstacles or accidentally setting the entire forest ablaze while evading the flames.
The dragon utilized every part of its colossal body as a weapon, from its teeth to its whipping tail and razor-sharp claws, not to mention its magical fire. However, regardless of its efforts, it proved unable to harm the nimble two-legged monkey who continued to mock it without fear, effortlessly bouncing from one spot to another.
And Sirius wasn't having an easy time either as it was taking all his physical as well as magical abilities to barely stay out of harm's way. He had too many close encounters with death to count and was only able to escape them by using the Conjuctivites curse which while didn't do too much to the Dragon but still stopped it in its tracks for a few seconds which was enough for him to dodge.
But the more worrying thing would be that none of Sirius's spells, be they curses, charms, or transfigured projectiles, seemed to penetrate the dragon's impenetrable scales. He was well aware of the creature's terrifying reputation from ancient times, but he had never anticipated being completely unable to harm even a single scale on its body. Fortunately, he had a plan in place; otherwise, the dragon would have merely had to wait for his magic to deplete before devouring him, since escaping was not an option with the Anti-Apparition ward still enveloping the forest.
Ducking beneath the meter-thick tail of the beast, Sirius swiftly retreated, preparing to defend against the expected flames. However, this time, the dragon hesitated, its mouth halfway open but devoid of fire. Curiosity prompted Sirius to steal a glance behind him, revealing the reason for the creature's hesitation.
Lying there in all its fearsome glory was the lifeless body of the dragon's comrade, the Basilisk. Even in death, the colossal beast sent a shiver down Sirius's spine. Its sideways position featured menacing red eyes glaring hatefully at the surroundings, while its cavernous mouth, large enough for Sirius to enter, revealed the sharp, yellow teeth that still dripped with the most potent poison known in this world.
Numerous swords jutted out from the upper jaw of the fallen creature, the cause of its agonizing demise. And it wasn't just a few swords; the entire mouth was littered with gleaming blades, creating a fearsome sight that made Sirius pause for a moment to absorb the gravity of the situation.
Sirius redirected his focus to the dragon, observing its gaze fixed upon the fallen Basilisk with an inexplicable semblance of emotion. The sight gave him a brief pause, but he knew he couldn't afford to hesitate any longer; his survival depended on it. Resolutely steeling his heart, he taunted the creature once again, "What's the matter, little lizard? Are you afraid of hurting your dear friend? But it's already dead, so I'm quite certain it won't feel a thing—"
His words triggered a complete loss of control in the Black Dread. It unleashed a torrent of scalding flames, engulfing both Sirius and the head of the Basilisk. Acting swiftly, Sirius conjured his most dependable shield but this time he added a thick plate of water on top of it.
While his mastery over elemental magic was not on par with the likes of Voldemort or Dumbledore, he possessed enough skill to summon and manipulate a limited amount of water effortlessly. As intended, the intense heat transformed the water into billowing steam, shrouding the surroundings in a dense white fog, obstructing the dragon's vision. Sirius, however, remained unhindered thanks to his keen magical senses.
As soon as the dragon ceased its fiery assault, Sirius wasted no time as he ripped his secret weapon from its place propelling it directly into the gaping maw of the Black Dread. The dragon appeared momentarily bewildered, behaving almost like a common mammal, involuntarily swallowing what it presumed to be food.
That proved to be the gravest mistake of the dragon's existence. The consequences were nearly instantaneous—its eyes bulged, and it stumbled about as if intoxicated. It coughed and hacked, as though attempting to expel its throat. Opening its mouth to roar in agony, it emitted nothing more than a feeble whimper. The dragon felt as if its insides were liquefying, as though its veins coursed with acid instead of the usual magical blood.
As the fog gradually dissipated, the dragon fixated its hateful gaze upon the source of its torment. It took a faltering step toward the two-legged figure, its intent to deliver one final bite evident. Unfortunately for the creature, its hind leg gave way, causing it to crash to the ground with a resounding thud that reverberated through the earth.
Lowering his wand wearily, Sirius addressed the beast, "Rest now." After a few seconds, the feeble rise and fall of its chest ceased altogether, marking the conclusion of the ancient creature's life, the final representative of its species taking its last breath.
...
"What the fuck!" Celine suddenly exclaimed from where she was standing leaning against the entrance while holding onto her wand tightly, not that it was any more useful to her than a normal stick at the moment with no magic inside her, "How did it die?" she shouted the question at Sirius.
"Didn't you see?" Sirius responded, a smug tone lacing his words as he gazed at her, watching her unsteady approach, still suffering from the effects of magical exhaustion—nothing out of the ordinary considering the circumstances.
"No... One moment, there was fog everywhere, and then... the dragon suddenly started dying out of nowhere," Celine replied, shaking her head in confusion. She turned to Sirius, seeking an explanation. "How in Merlin's name did you do it?"
"Care to guess?" Sirius replied, his voice teasing.
"Stop playing games, you bastard, and tell me!" Celine exclaimed, frustration evident in her wide eyes as she looked into his frustratedly, "I am dying from suspense here,"
"Fine! Fine!" Sirius rolled his eyes, his expression turning serious. He rubbed his imaginary beard, attempting to imitate Dumbledore. "You see, my dear, I deduced from my previous battle with the dragon that defeating it with spells alone would be nearly impossible unless I could cast hundreds of them continuously. So I knew I had to find another way..."
"And?" she pressed, disregarding his sagely act as much as she could.
"And so, my dear," Sirius continued, "tell me, what is the one thing in this world that can kill someone from the inside, rather than the outside?"
"What? Did you send another rat to the dragon?"
"No... Obviously not!" Sirius responded, shaking his head in disappointment. "The dragon was far too intelligent to fall for that trick after seeing it once. Think again."
"Um... I can't think of anything like—" Celine's voice trailed off before a realization struck her. Her eyes widened as she peered into the open mouth of the giant serpent, and she promptly identified the missing piece. "It's missing one of its front teeth," she whispered breathlessly.
"And you know where it is," Sirius said, smugness evident in his voice as he moved toward the dragon's lifeless body. Waving his wand, he carefully raised the dragon's upper jaw, instantly assaulted by a nauseating breath so potent that it made him want to empty his stomach. 'Guess old Herpo didn't think to provide toothbrushes for his pets,' he mused inwardly.
"You're quite clever..." Celine marvelled, her amazement apparent as she observed the Basilisk's front tooth lodged inside the dragon's throat. She never would have considered employing one beast to kill the other.
"Of course, I am!" Sirius attempted to convey his smugness, though his pinched nose compromised the effect, leaving him sounding nasal.
"You're still an idiot," Celine scoffed, rolling her eyes. However, a small smile tugged at her lips. "Now, close the damn thing before we suffocate," she added, a few steps behind Sirius, but the stench was still overpowering.
"As you wish, My Lady—"
"Wait!" Celine interrupted, squinting her eyes at the massive jaws. "Do you see that metallic object hanging in its throat?"
"Hmm..." Sirius scrutinized the area until he spotted it. "I see it!"
"Summon it!"
"Sure..." Sirius shrugged before pointing his wand and casting, "Accio!"
What emerged from the dragon was a sizable, silver metal arc, roughly the size of Sirius's hands—a third of a part of a ring. Intricate runes adorned its surface, so densely packed that discerning their purpose seemed impossible.
"Do you think it's the—" Sirius began to ask, but Celine abruptly stood up and darted toward the open mouth of the Basilisk. She peered intently into the encompassing darkness and triumphantly called out after a few seconds, "There's another one here!"
Sirius joined her swiftly, confirming the presence of a similar metallic arc inside the serpent's lifeless body. Without wasting a moment, he summoned it towards himself, being careful not to touch it, unsure if any Basilisk venom remained.
Floating the object to the ground, Sirius performed a simple purification charm used in Potions, removing all foreign matter from the arc. He gingerly picked it up, then carefully brought the two pieces together. As expected, as they neared one another, they began to glow brightly, swiftly flying into alignment and merging into two-thirds of a ring-sized bangle.
"So, this is the key, huh," Sirius marvelled, playing with the shimmering silver arc, illuminated brilliantly under the sun.
"Yes, at least a part of it," Celine replied with a smile. "This is how the ward is supposed to function—one part protected by each guardian, concealing the secret."
"So the only thing left is to go to the final piece in the Nundu," Sirius said while looking toward the direction where they had fought and killed that beast using lightning before he gibed, "Hoping that it hadn't been eaten by animals already,"
"There's no way anything could survive eating that thing," Celine shook her head with a scoff while thinking about the fearsome poison fog it had unleashed. She followed Sirius's gaze and let out a tired sigh. "It would be quite a trek from here..."
"Ah! We could do that, or..." Sirius said, turning to her with a mischievous smirk, "We could simply Apparate."
"What?"
"Didn't you notice? The moment the dragon perished, the Anti-Apparition ward cast over the entire forest automatically shattered," Sirius explained.
"That's perfect, then!" Celine exclaimed, her joy evident. "What are you waiting for? Let's go!"
"As you wish, my lady," Sirius bowed theatrically before taking Celine's hand. With the partially completed key in his other hand, he disapparated with a resounding pop.
In the next instant, they materialized in the clearing where they had summoned the ritualistic lightning and had subsequently fled, sans clothing, from the dragon and the Basilisk. The Nundu's lifeless body lay undisturbed, just as they had left it, with no creatures venturing near the surrounding area.
Thankfully, the poisonous field had dissipated, making it easier for Sirius to approach the corpse and retrieve the final piece of the key from its mouth.
"Let's do this," Celine urged eagerly, and Sirius nodded. He promptly joined the arcs together, holding them in his hands. Once again, both pieces emitted a brilliant glow before merging into a complete silver ring.
As the fused key took form, an earth-shaking rumble reverberated throughout the entire forest, startling birds into flight. The pair turned their attention to the source of the sound, which seemed to suggest that the very earth was being torn apart, something powerful forcing its way through.
"I think I know where that is," Celine suddenly said, once the noise subsided.
"Where?"
Instead of answering him, she asked him to take out the previous map. Sirius brought it out of his pouch and opened it, it was full of all the markings they had made at the start of their expedition, all the places they had set up camp as well as the area they had scanned.
'It feels as if months had passed,' Sirius thought to himself while Celine studied the map. After a while, she pointed to a spot near the centre and exclaimed, "Here!"
"Because it's in the middle of the locations where we found the beasts?"
"Exactly!" Celine nodded enthusiastically. "I believe it should be close to our third camp... You remember it, right?"
"I think..." Sirius replied, closing his eyes and pondering for a moment.
"Let's go, then," she declared, placing her hands on his shoulders. With their goal now within reach, impatience crept into her voice.
Sirius closed his eyes to concentrate, and in an instant, they disapparated once more. They arrived beside the lake where they had set up camp, and as Sirius looked up, his breath caught in his throat. He whispered, "That wasn't there before, was it?"
"No..." Celine replied, swallowing hard. "No, it wasn't..."