When more people know a secret, the risk of exposure increases exponentially, as both Dumbledore and Snape knew and experienced.
That's why, to ensure the plan continued smoothly and minimize the chances of failure, Dumbledore didn't even tell Professor McGonagall and the others initially.
But...
Who let Fish find out?
In fact, when he recruited Fish into the gang, he was already mentally prepared for Professor McGonagall and Hermione to know the entire plan, but Professor Slughorn and Madam Pomfrey definitely weren't among them.
Professor Slughorn was fine since he already knew about the Horcruxes and had some connection to them, and Dumbledore only had to mention the Horcruxes briefly before he felt too embarrassed to express his displeasure.
But Madam Pomfrey was a small problem. Not only had she worked with Dumbledore for a long time throughout the school, but she had stayed at Hogwarts because Dumbledore had wanted to recruit her.
"Ahem! Poppy, I had to do it for a reason..." Dumbledore coaxed Madam Pomfrey, taking the time to shoot a disgruntled look at Snape.
"They said they wanted to try to heal you, I couldn't stop them, could I?" Snape gloated. "I warned you before, you're giving him too much time, a skilled Potions master could still see the flaws."
The good thing was that Madam Pomfrey wasn't someone who didn't know what was important. She was genuinely angry about being deceived by Dumbledore a moment ago, but after calming down, she figured he probably had something planned... After all, Dumbledore, though often a bit crazy, wouldn't joke about such things.
"Albus, what compels you to deceive everyone by pretending to be dead?" Madam Pomfrey asked.
She didn't need Dumbledore to answer, but she had a pretty clear idea of the reason. Who else would he need to go to such lengths for if not You-Know-Who.
Unable to hide it any longer, Dumbledore had no choice but to involve Professor Slughorn and Madam Pomfrey, thanks to having asked Harry to obtain Professor Slughorn's memories, so Dumbledore could know he could be trusted.
"It all started when Fish came to see me in his second year with a black diary..."
...
"What's the situation? Where is Madam Pomfrey?"
Hagrid, who had been watching the door when Snape and Professor Slughorn returned to Professor McGonagall's office, was the first to rush and ask nervously.
Professor Slughorn sighed, shook his head with a mournful expression, and said, "Albus has two powerful and ancient dark magics entwined in his body, fixing just one is already difficult for me, and in this case... I'm sorry, there's nothing I can do..."
"Madam Pomfrey is taking care of Dumbledore, you should leave him be for now," Snape added from the side.
Mainly because Madam Pomfrey wasn't a very good actress, and Dumbledore was concerned that she might show flaws, so he simply used it as an excuse to keep her away from others' questions.
Hagrid lamented and covered his face with his huge palms, tears streaming through his fingers and staining his beard and the front lapel. Several of the other professors also seemed sad, and for a while, the only sound in the office was Hagrid's sobbing.
Professor Slughorn, feeling somewhat guilty for lying to his colleagues, gave Hagrid and the others a remorseful look and quietly said, "I'm sorry, I'll go back first..." before turning around and leaving the room.
The others limited themselves to thinking that they were blaming themselves for not being able to heal Dumbledore and did not suspect anything...
After all, the others would never have imagined that several of their colleagues, including Madam Pomfrey and Professor McGonagall, would join forces with Dumbledore to deceive them, all the students at Hogwarts, and the entire wizarding community, by claiming that he was "gravely injured and dying."
As the rumor was "confirmed" by the students and professors at Hogwarts, the news of Dumbledore's imminent death spread throughout England and other countries.
The Daily Prophet, in a departure from its attitude the previous year, dedicated a lot of space to Dumbledore's collaborations.
This confirmed the truth of the rumor, and the entire wizarding community of England plunged into mourning.
Dumbledore had taught and been the headmaster of Hogwarts for many years and had been an absolute force in the fight against Voldemort for over a decade, as well as a benefactor to countless wizards.
Even pure-blood wizards who did not share his beliefs sent letters and condolence gifts to Hogwarts upon learning of Dumbledore's imminent death.
Some connected the recent attack on Hogwarts with Dumbledore, believing that he had probably been gravely and irreparably wounded while protecting his students at that time.
Enraged people began sending letters to the Ministry, demanding that Umbridge and the others involved in the attack, as well as the mastermind Cornelius Fudge, be hanged.
Amidst all this turmoil, the Hogwarts students completed their final exams and, while waiting for the results, received the news of Dumbledore's death.
There was a grand funeral at Hogwarts. Many wizards came from all over the world to attend Dumbledore's funeral, in addition to the entire staff and students of Hogwarts. Even Madame Maxime flew to Hogwarts in her carriage, pulled by enormous Abraxans.
Naturally, someone from the Ministry also came, and Pius Thicknesse, under Voldemort's control, was there in person, asking Professor McGonagall to see Dumbledore's body.
Professor McGonagall knew what he was really doing: identifying Dumbledore's body for Voldemort.
However, Professor McGonagall agreed to his request because Fish had already asked Winky how Barty Crouch Jr. had been replaced by Barty Crouch in Azkaban.
This time, Dumbledore had faked his death in the same way. They had found an old wizard who was truly dying, and after obtaining his permission, they had given him Polyjuice Potion with Dumbledore's hair.
After "seeing" Dumbledore's body, Pius sat with his men by the Black Lake, satisfied.
Once the seats by the Black Lake were filled, the funeral began.
From the Black Lake came the singing of the murlocs, singing in a strange language that only Fish understood, the song was not harsh, but it sent shivers down their spines.
Then Fawkes, who had been perched on Fish's shoulder, lifted his head and sang a beautiful but sad song to the melody of the murlocs.
But to Fish's ears, Fawkes's song was not sad at all because the words that came out of Fawkes's mouth were,
"Albus Dumbledore is a great fool~ Why do I have to sing such a boring song~ What a bother! What a bother! What a bother!"
Fish tensed their face, with their tail lashing behind, forcing themselves not to sing along with Fawkes.
Finally, when a tearful and red-eyed Hagrid carried the corpse, wrapped in purple velvet adorned with golden stars, to the marble table at the front, the murlocs' song ended, and Fawkes stopped.
A small man with thick hair and dressed in a black robe stood up from his seat, stood in front of Dumbledore's body, and began reciting the praise that put Fish to sleep, although Fish tried to maintain a serious expression on their face to not give it away.
Finally, after the praise ended and the small wizard returned to his seat, Fish saw dazzling white flames leaping around Dumbledore's body and the table. The flames grew higher, obscuring the body.
White smoke rose in the air, taking on peculiar shapes. For a moment, it seemed as if a phoenix had joyfully flown towards the sky, but then the flames disappeared, revealing a white marble tomb that enveloped Dumbledore's body and the table on which he had been placed.
Numerous arrows flew out of the forest like a rain, soaring into the sky and falling far from the crowd. The centaurs bid farewell to Dumbledore.
After the shower of arrows, the centaurs turned their bodies and vanished into the shadows of the trees. The murlocs slowly sank into the water, disappearing from sight.
Fish twitched their ears, suddenly thinking that Dumbledore's situation at Hogwarts could be very precarious after defeating Voldemort.
(??ω??)