"I don't believe you understand the soul, Mr. Hart," Gellert Grindelwald said with grave seriousness. "I have some knowledge of the soul's layers, which is precisely why I know how utterly foolish it is to split a soul..."
"Could you elaborate?" Jon frowned and asked promptly.
"The soul and magic exist on entirely different planes..." Grindelwald spoke slowly. "Magic belongs to the material world. In most cases, its influence is confined to that realm. Of course, some advanced spells can penetrate the mind by affecting the brain, thereby entering the spiritual realm. But such magic is exceedingly complex and dangerous..."
"Like the Memory Charm and Legilimency spells?" Jon asked softly.
"Exactly... Spells capable of affecting the spiritual realm are exceedingly rare and exceptionally difficult to wield. We prophesied that Predictmagus possesses an innate, unparalleled talent for spells operating at the spiritual level. This is one reason I believe Predictmagus is the world's will's spokesperson..."
"Then what about the soul? Is the soul also part of the mental realm?"
"No. The soul transcends both the mental realm and the physical world... Thus, for the higher realms of the soul, magic is fundamentally powerless. It cannot influence..."
Jon couldn't help but interrupt him.
"But I've heard some spells can affect souls—like the Killing Curse. Its principle is to destroy the soul..."
"Nonsense!" Grindelwald suddenly sat up in bed. "Who told you that?"
"Um..." Jon hesitated before answering. "That guy named Tom Riddle..."
"Then he's an idiot!" Grindelwald rolled his eyes in disdain. "The essence of the Killing Curse lies in stripping the target of their life force, compelling them to obey death's command. It has nothing to do with the soul level!"
"The greatest proof is that the Killing Curse cannot kill a phoenix. You must understand that phoenixes possess souls. The source of phoenix power lies precisely in its influence on the soul level. When the Killing Curse strikes a phoenix, its body is utterly destroyed in an instant... Yet the miraculous power of the phoenix allows them to be reborn from the flames."
As he spoke, Grindelwald frowned slightly, as if recalling some unpleasant memory.
"Alright, sorry... I understand!" Jon nodded quickly.
"The Killing Curse does indeed affect souls, but only indirectly... Its principle is to decree death. When a living being dies, unless they choose to become a ghost, their soul dissipates swiftly..."
"Is that also why Horcruxes can evade death?" Jon asked softly.
"Exactly... A wizard possessing a Horcrux can survive even if their body is destroyed, attacked, or shattered, because a portion of their soul remains intact in the world. As long as the Horcrux remains intact, the remaining soul fragment remains unharmed. But if the body is destroyed, they become a state even lower than a ghost. Conversely, if the Horcrux is destroyed, the remaining soul fragment vanishes instantly."
Jon nodded thoughtfully.
...
"Magic cannot directly affect the soul, but it can indirectly serve as a medium for the soul." Grindelwald paused, then suddenly continued.
"Take, for instance, that 'Fidelius Charm' Dumbledore was so fond of. Its principle lies in concealing secrets within the soul itself. Since magic cannot directly influence the soul, that damned charm is utterly unbreakable... I learned that the hard way."
"Then there's the soul-splitting method used in Horcrux creation… Its essence involves murdering a wizard, then using a spell to provoke a brief, furious outburst from their soul after death, thereby tearing apart one's own soul… Frankly, it must be an excruciatingly painful process."
"Indeed." Jon nodded thoughtfully.
He suddenly recalled a certain great Dark Wizard who had endured such agony a staggering seven times. That spirit of perseverance was truly worthy of admiration.
"Wait..." Jon's eyes suddenly lit up. "When you said there was another way, you meant using one soul to tear another apart?"
"Yes. Magic itself cannot harm a soul, but it can serve as a medium—influencing and damaging the soul." Grindelwald's expression grew grave. "This is likely the only method, though its feasibility is exceedingly slim."
"Indeed!" Jon couldn't help but sigh.
"After a wizard is killed, his soul becomes feeble and decays at an alarming rate. Compared to a Blood Curse soul that's been incubating for fifteen years, it's utterly incomparable..." Grindelwald continued.
"So this deceased wizard's soul couldn't inflict significant damage on the Blood Curse soul. Even if it succeeded completely, it could only delay the curse's activation for a short while at best."
"That's why I call it a method with minuscule chances of success... Not to mention, you killed their wizard yet expect his soul to help you combat the blood curse soul—that's equally unrealistic..."
"If the dead wizard's soul chooses not to aid you in attacking the blood curse soul but instead tears apart a normal soul, it would only accelerate the blood curse's onset, backfiring completely."
"Alright, thank you!" Jon nodded solemnly, then rose from the floor.
A faint, bitter smile touched his lips.
"At least there's still hope, right?"
"Yes." Grindelwald nodded in agreement, casting a sympathetic glance at Jon.
...
The sky had grown completely dark.
Thin moonlight filtered through the narrowest cracks in the black stone walls, illuminating the lonely cell.
"In all these fifty years combined, I might not have spoken as much as I have today," Gellert Grindelwald remarked wistfully.
"If you'd like, I'll come visit you more often from now on," Jon replied.
"I might not get the chance... Next time you come, it might be to prepare my funeral!" The old wizard gave a somewhat desolate chuckle. "If I die, bury me... bury me..."
"...bury me in Braunau, Austria. That's my homeland!"
"Understood. I'll remember."
"Where are you headed now? To Hogwarts?" the old wizard asked finally.
"No..." Jon shook his head. "I must go to Albania."
"Albania..." Grindelwald reclined back onto the stone bed. "Good luck... If I recall correctly, it's a land under Curse."