Dumbledore thought for a moment and said, "This involves a terrible dark wizard in the fifteenth century, Axtis. He was the earliest known resident of Azkaban. At that time, it was just an unknown island in the North Sea, blocked by hidden magic.

Although there has never been a shortage of dark wizards called 'evil' in history, Axtis's evil is rooted in his bones. He has no mercy on all living things. It was he who created the Dementors by cruel means."

Felix said in surprise, "Dementors were created by wizards? Just like the five-legged monster?" He didn't know at all. This is definitely a secret of the wizarding world.

"The five-legged monsters were an accidental product, but the Dementors were not." Dumbledore shook his head. "When Axtis died and the concealment magic failed, people discovered what he had done, but the Dementors had become an independent species. At first, there were only a dozen of them, but they could grow and split like fungi, and conventional spells were almost ineffective."

Felix said puzzledly, "If that were the case, their number would have been out of control long ago, but in fact, they are rare and used by the Ministry of Magic?"

Dumbledore explained, "The Ministry of Magic and the Dementors are more of a cooperative relationship, and this creature seems to have a magical group consciousness. Their number is always maintained within a certain range, but as long as it is reduced to a certain level, they will split on their own. Perhaps this is also a way of reproduction?"

Felix almost understood the existence of the Dementors. He couldn't help asking, "Besides the Patronus Charm, what other spells are effective? I mean, can it completely kill the Dementors?"

"It's difficult, Felix, it's difficult." Dumbledore said.

Felix wanted to continue asking, but Dumbledore was obviously unwilling to talk more, and their conversation soon ended.

...

In the early morning, the little wizards woke up from their beds, knowing nothing about what happened a few hours ago.

Harry, Ron and Hermione sat at the Gryffindor table and ate breakfast. Owls flew in from time to time, and Hermione looked outside the hall with expectation.

"Are you waiting for a letter?" Ron asked.

"Oh, I bought a book from Flourish and Blotts through the Owl Shed." Hermione said absentmindedly, "It seems that I can't get there today." Ron

saw that Harry was a little depressed, and suggested, "When you finish your training on the weekend, we can go to Hagrid's place as a guest. To be honest, the three-headed dog is very cute after it becomes smaller. This is the first time I agree with Hagrid's aesthetics..."

Harry was also moved. He said excitedly, "It may be later. Wood should train until dark."

Ron shrugged, "I hope Hagrid won't kick us out again." At the beginning of the school year, because they were worried that Hagrid would be expelled, they went to visit him at night wearing invisibility cloaks. As a result, Hagrid personally escorted them back to the castle and warned them that they could only visit him during the day.

Hermione was about to express her opinion, but Professor McGonagall suddenly walked into the hall. She shouted, "Potter, come here!"

Harry put down his knife and fork in confusion. What had he done wrong? Ron and Hermione looked at each other and followed him.

"Weasley and Granger... it's okay if you're here." Professor McGonagall did not drive away the two uninvited people. She looked at Harry with a serious expression: "Where is your peephole? The one for Black!"

Harry carefully took out the pocket peephole from his pocket. It was lying quietly in his hand. Professor McGonagall was obviously relieved.

"What happened, professor?" Hermione asked in a low voice.

"I shouldn't hide it from you anymore, Potter," Professor McGonagall said, "I know you may be shocked, but I have to tell you, Black"

"I know everything," Harry said angrily, "I know he is chasing me. This is the reason he escaped from Azkaban! I also know that he has a good relationship with my father and is even his best man. He, he is still..." Harry couldn't say anything more. When he thought of the word godfather, he felt insulted, including his deceased parents.

Professor McGonagall seemed very surprised and stared at him, "I see, okay, I thought..."

"Then you should understand why I asked you to carry this looking glass with you at all times, it can protect you." She pursed her lips, "Just earlier today, before dawn, the castle's looking glass sounded the alarm."

Harry stammered, "Is it, is it the looking glass in my hand? But it's been in my pocket the whole time, there's nothing unusual?"

Ron's face also showed a frightened expression, he covered his pocket tightly and whispered, "Don't move, Scabbers!"

Professor McGonagall clenched her fists repeatedly, as if she was hesitating whether to tell it out. Before, in order to keep it secret, only Felix, Dumbledore and her knew that there were not one but three looking glasses, but now it is no longer a secret.

Hermione at the side continued, "Professor McGonagall, I saw from Professor Happ that there are three similar peepholes in total. The other two should be placed somewhere else? I guess they are at the entrance of the castle..."

Professor McGonagall sighed, "Well, Granger, it's just like you said... one is placed at the front door and the other is placed at the back door."

Harry didn't know whether to be relieved or disappointed and said, "So, he once wandered around the entrance of the castle?"

"That should be the case," said Professor McGonagall, "The professors all got up early and searched the castle urgently, but found nothing. No strangers were found in the portraits in the castle, which means..."

"He knew he was exposed and ran away in advance." Harry said.

"That's right, Potter." Professor McGonagall said, "Since you know everything, I believe you are mentally prepared. Some activities are not suitable."

"Hogsmeade," Harry shouted, his heart suddenly rose to his throat.

Hogsmeade is a village composed entirely of wizards. Little wizards above the third grade can come here to play on specific days of each school year with the permission of their parents or other guardians.

He discussed this with Ron last night. He told Ron that he did not get Uncle Vernon's autograph. Ron suggested that he try to find Professor McGonagall.

Now it seems that the plan may be ruined.

Professor McGonagall glanced at him and said seriously: "Of course you can't go to Hogsmeade. I'm talking about Quidditch. To be honest, it is too dangerous to let you train. Even if there are other players, they are not enough for Black to deal with alone."

"Professor McGonagall," Harry couldn't help but yelled, "What does this have to do with my training?"

"Of course it is related. Black is very likely hiding in Hogsmeade or deep in the Forbidden Forest." Professor McGonagall said a bolt from the blue. "The Quidditch field is too far from the castle. If something happens, we won't be able to rescue him in time."

"But, but..." Harry said somewhat dazedly. He had already started this year's training, three times a week. Wood ambitiously told him that he wanted to win the second Quidditch Cup during his tenure as his graduation gift.

The other players also seemed confident because of last year's victory.

But now the first game hasn't even started, is the trophy going to become a bubble?

Harry suddenly thought of something, and he said anxiously: "Professor McGonagall, if there are professors watching us, such as Madam Hooch..."

Professor McGonagall pursed her lips and said nothing.

"Please..." Harry pleaded. "

Okay," Professor McGonagall softened her tone, "I will ask Madam Hooch to supervise your training, and return to the castle immediately before dark. When I'm free, I'll go there too."

She left in a hurry, because she had a lot of things to deal with because of the accident this morning.