The Butcher of Hogsmeade

The space above the water on the stone steps was very limited, only enough for Dumbledore to stand on. Fortunately, the water level here was much shallower than at the entrance to the crevice, so everyone could stand up from the water and expose their upper bodies above the surface.

Dumbledore stood on the steps, oblivious to the water still dripping from his soaked robes, and looked up to survey his surroundings. The tip of his wand shone brightly, but strangely, the light could hardly travel more than five feet. Beyond that distance, the light seemed to be swallowed up, making it impossible to see the entire cave.

Shen Hou believed that with Dumbledore's abilities, the Illumination Charm he cast could not have been this dim; once he understood this, his fear of the surrounding environment inevitably increased.

"Just like when I came in last time, apart from this set of steps, there are no signs of any artificial alteration." Dumbledore's voice rang out, sounding unusually muffled in the narrow space.

"What does that mean?" Fabian asked.

"This means it's just a vestibule at most, nothing important." Dumbledore turned to look at the stone wall that the steps led to, most of which was bare except for some moss growing in the corners and crevices. "Clearly, the entrance has been hidden by magic."

No one spoke; each held immense trust and waited for Dumbledore to resolve the issue. Of course, another, more important reason was that no one could discern any hidden magical traces on the bare stone wall.

Considering that everyone present except Shen Hou is a Hogwarts graduate, if this weren't Voldemort's secret lair but rather a quiz in class, the headmaster would probably give each of these academic underachievers a good scolding.

After a few minutes, or perhaps a little longer, during which Dumbledore walked back and forth along the stone wall twice, sometimes almost lying down on it, examining every line and crevice inch by inch with his wand and his free hand; then he stepped back a few paces, stood at the bottom of the steps, and pointed his wand at the stone wall.

In an instant, a bright, arc-shaped outline appeared on the stone wall, as if a strong white light was shining from behind the wall, piercing through the arc-shaped gap and reaching everyone's eyes. But before the crowd could cheer, the light, along with the gap in the stone wall, vanished rapidly.

Dumbledore walked back to the stone wall, and after a moment, sighed and shook his head: "No way, so barbaric, and so... superficial?"

"What's wrong, Professor?" Sirius, who was closest to the professor, couldn't help but ask.

"I believe this magic requires visitors to pay a price before they are allowed to pass." Dumbledore pulled a small silver knife from his pocket, which looked smaller than many household fruit knives.

Sirius asked hastily, "What's the price?"

"Blood, and it must be magical, readily available blood." Dumbledore said with disdain, clearly scoffing at the workings of this hidden magic. "This only makes me more certain that this cave was indeed set up by Tom himself, and unsurprisingly, he has once again disappointed us. It seems he can only think of using pain and injury to weaken those who enter this cave."

"Wait a minute!" Seeing Dumbledore about to stab himself with a knife, Sirius rushed forward and almost brute forcefully snatched the knife from the old wizard's hand. "There are so many of us here. It would be too useless to make an old man bleed."

Sirius's hands moved much faster than his words. Before he could even finish his second sentence, he had already slashed a large gash in his palm; blood dripped out and trickled onto the ground. Only then did he belatedly ask, "What should I do next?"

"That's not how it is." Dumbledore shook his head helplessly, waved his wand at Sirius's hand, and the blood that was flowing down was lifted up by an invisible force, spread into even patches, and sprinkled on the stone wall; after a while, the bright arc outline reappeared, and this time it did not disappear.

"That's enough." Dumbledore waved his staff again, and Sirius's hand wound immediately stopped bleeding.

"That's it?" Sirius shook his hand, looking at the increasingly bright arc outline, still feeling incredulous.

Dumbledore nodded. "That's enough. What else do you want?"

"I thought I'd have to have almost half my blood drawn!" Sirius shook his head, as if to tell others that losing this little bit of blood wouldn't cause him any stress.

"Blood is the vessel of the soul, and the strength of a wizard's magic depends on the strength of his soul." Dumbledore seemed to be using the cave as a classroom at this moment. "Losing blood means temporarily weakening a wizard's spellcasting ability; of course, he dared not ask visitors to donate too much blood, otherwise they would have to find other alternatives."

Sirius listened in bewilderment, while James asked thoughtfully, "Professor, this content doesn't seem to have been mentioned in class before; not in Charms, Potions, or Defense Against the Dark Arts."

"Oh, the relationship between soul and blood, that's alchemy, and Hogwarts doesn't have that course; however, if you study ancient runes or potions in depth, you might have a chance to come across some of it, but it certainly won't be complete... Ah, the entrance has appeared, so let's put the discussion of alchemy aside for now!" Dumbledore explained, and then the section of stone wall smeared with blood suddenly vanished into thin air, revealing a dark entrance.

Following behind the old wizard, Sirius whispered to James, "A discussion about alchemy? Lily might be able to say something, but us... is that even a topic we can discuss?"

James shrugged, made a guilty face, lit his wand, and followed closely behind the old professor through the archway in the stone wall.

Behind the archway, a strange sight unfolded before the intruders: a vast black pool lay before them, the surrounding darkness swallowing the light emanating from the wand as always, making it impossible for anyone to see beyond five steps; the cave ceiling was invisible above, and the other side of the pool was also obscured in the distance.

A faint, misty green light shone in the center of the pool, making it difficult to distinguish between real light and reflections on the water's surface.

"Be vigilant, gentlemen," Dumbledore warned. "The space within the arch is sealed by dark magic, which forbids Apparition. Remember, this is extremely dangerous dark magic, not the anti-Apparition charm you encountered outside. You must overcome your Apparition instincts when in danger, or it will be fatal. Also, do not approach the water."

"What's in the water?" Fabian was not entirely at ease.

Dumbledore did not answer, but instead shot a bright ball of light towards the surface of the pool, looking like an old-fashioned battlefield flare.

The ball of light swept across the water's surface, and the previously stagnant water suddenly erupted. A grayish-white shadow leaped out from underwater and grabbed at the ball of light above.