The Dark Lord's secret? Sirius was surprised, and he suddenly sensed that Regulus' death might have something to do with it, and hurriedly asked.

"What secret, did Regulus tell you?"

"Master Regulus didn't tell Kreacher." The old house-elf shook his head, "Kreacher only knows that after that the Dark Lord begged Master Regulus for a house-elf. ”

"Looks like it has something to do with this locket!" Lupin affirms that Regulus is willing to destroy this thing at the cost of his life, which shows that it is important.

Ivan understood that Regulus was referring to the mystery of Voldemort's immortality - Horcruxes!

From this, it can be inferred that there must be a record of Horcruxes in the Black family's library.

Regulus probably had read the books in the early years and had some impressions, and then he happened to be there when Voldemort killed people to make Horcruxes, or Voldemort showed his bottom somewhere else.

Anyway, Regulus had some guesses in his mind, so he went back to the library to look through the books to find more information.

Thinking of this, Ivan turned to look at Kreacher and asked. "Kreacher, do you remember all the books Regulus read?"

The house-elf shook his head again, the books that Master Regulus had read in those days were piled higher than it, and it had been more than ten years, and it couldn't remember it clearly.

"Shall we just go to the library and look for it?" Lupin suggested that they only need to do what Regulus had done once.

"That's right! But be prepared, there might be a bit of a lot of books out there! Sirius spoke.

Many? How many can there be?

Ivan really didn't have a concept in his mind, he had already read several books, and no matter how much more could he compare to Hogwarts?

But when Sirius led them into the underground library, everyone was shocked.

"There are too many books here, right?" Ivan looked around and couldn't help but stammer.

The entire library is like a square, with rows of bookshelves neatly arranged, and there is no end in sight at a glance.

It's just that because it has not been taken care of for a long time, it is covered with dust, and some of the tight bookshelves are even cobwebs.

"That's all Blake's collection of books he's been amassing over thousands of years!" Sirius explained with a smile, a little proud in his words, I am afraid that no family in all England has more books than the Black family.

"But if we're looking for them one by one, when are we going to find them?" Harry asked a difficult question.

Sirius' smile was stuck on his face.

Fortunately, although Kreacher didn't remember every book Regulus read, he still had some impressions of the area where Regulus had been, which directly narrowed down the search.

After determining the approximate range, everyone split up to find out.

Ivan casually found a bookshelf, his eyes swept over and checked the name of each book, knowing that he only needed to find books related to souls and deep black magic related to Horcruxes.

However, Ivan is also a little helpless, he knows everything, but he needs to pretend that he doesn't know, if it weren't for his good acting skills, I'm afraid he would have exposed himself a long time ago.

It's good to take the opportunity to get the Horcrux thing on the table now, so that you don't have to lie every time you face this problem.

Ivan scanned the books on the shelves, and from time to time he pulled out a few and opened them, and when he found that there was no record of a Horcrux, he put them back.

Just like this, Ivan unexpectedly saw a magic book that was not put back in the shelf, but just leaned against the corner of the shelf.

There was some dust on the paper, and only pictures and a few staccato words on the cover could be faintly seen.

Ivan couldn't help but feel a little familiar, and after picking up the book with his hand, the touch proved it even more, the cover felt significantly different from other books, a bit like touching the skin.

"Whew~" Ivan gently blew off the dust on it, and the cover of the book gradually appeared, and it was written on it - "Cutting-edge Black Magic Decryption"!

Looking at the title of the book on the cover, Ivan's pupils shrank.

He hadn't forgotten that when he was in his first year, he found an identical book in the forbidden section of Hogwarts.

At that time, my strength was not qualified enough, I couldn't crack the magic above, and I was busy looking for "Bloodline Origin", so I didn't have time to check it.

When Ivan thought he could break through the defenses, he watched "Cutting-edge Dark Arts Demystified", but the book disappeared, and he searched the entire forbidden book section but couldn't find it. There is a high probability that it was hidden by Dumbledore, but I didn't expect there to be a copy here!

However, it is also true that the Black family, as the oldest wizarding family in the British wizarding world, has most members who are biased towards dark wizards, so it is normal to have this kind of high-end collection of dark magic books.

Regulus probably learned the mysteries of Horcruxes through this book.

Ivan recalled the protective mechanism he encountered when he opened the book, and gently touched his hand to the cover of the book, sensing the movement of the magic, and found the node after about a few seconds.

"Stop!" Ivan pressed his wand against the node, entered the mana, and the title text on the cover slowly lit up, and after a moment it gradually faded again.

Soon, Ivan felt the book in his hand tremble as if it had life, and opened it automatically.

The difference is that this time there is no black fog or human faces, and there is no scream that seems to hit the soul.

The corners of Ivan's mouth curled, and then he began to open the contents of the book.

However, after turning a few pages, Ivan's face became very serious, and he only felt a chill welling up in his heart.

Vicious curses, inhumane sacrifices, self-mutilating black magic... What is recorded in the book is creepy.

To sum it up, it is harmful to others and to oneself...

After Ivan finished half of the book, the only thought left in his mind was the only thought that existed, and he understood why Peter Pettigrew, a mediocre Pettigrew, was able to blow up a street with a thunderbolt explosion.

Peter Pettigrew uses a kind of black magic that increases the power of the spell by self-harm, and the more painful he is, the more damage he receives, and the more powerful the spell bursts out!

And that's just the price of a finger, what if it's an entire arm or a leg?

Ivan couldn't imagine how much magic could be magnified,

Of course, it's not a good thing that the spell is too powerful, and if the caster can't control it, the magic will come back to the caster.

Countless wizards have died as a result, and almost every few years you can hear someone being killed or injured by their own magic...