Although Nimongard appears large from the outside, resembling a vampire-like castle described in Muggle storybooks, built on a cliff, once inside, you'll find there's really not much space here.
Even the lowest entrance is just about the size of a regular classroom, with a staircase taking up a third of it, and the uppermost floors are even smaller, leaving Grindelwald with seemingly only a bare thin blanket for company.
It seems there used to be a sheet, but now that has been torn to shreds as well.
Kael hesitated for a long time; perhaps Grindelwald's current state made him feel pity. He eventually laid a few pieces of parchment on the ground and, after a moment's thought, fetched out a bottle of ink.
"You'll probably need this too."
In this place, even letter paper had to be substituted with bed sheets, undoubtedly with no ink either. Grindelwald's mentioned writing letters most likely meant smearing blood on a sheet.
As for how he would send the letters out, Kael didn't know, and he didn't want to know.
"Aha, thank you." Grindelwald grinned.
"No need to thank me." Kael said, and he paused for a moment, "If you do anything unnecessary..."
"You'll kill me?" Grindelwald seemed to have heard a funny joke, laughing, "I've heard that said so many times... Different people, at different times, have all told me the same thing.
"But you're the bravest one. Those before you didn't even dare to linger an extra minute in front of me, even though I don't even have a wand."
"No, you misunderstand, I won't try to kill you." Kael shook his head.
Apparently not expecting Kael to say this, Grindelwald shifted his body, "So you're planning to let me go?"
"Sort of." Kael said, "You're a trouble I don't want to deal with right now, but if you manage to escape using what I gave you, I can't just stand idly by, pretending nothing happened."
"So, what do you plan to do?" Grindelwald asked with interest, as if curious about what interesting response Kael might come up with.
"I'll deal with Professor Dumbledore." Kael said calmly, "Once you leave here, I'll send him off to another 'Nimongard', ensuring you'll never meet, or even communicate again."
"Ha, hahaha..." Grindelwald laughed twice, falling back onto the blanket, "Your idea... is even harder than killing me."
"No, no, perhaps difficult for others, but not for me." Kael extended his hand, manifesting a golden line with magic power.
"Oh... Contract Magic?" Grindelwald raised an eyebrow, "What are you trying to say?"
"The other side of the contract is Professor Dumbledore."
Somehow, the person in front seemed a bit angry, clutching the blanket tightly.
But he didn't care, continuing to speak calmly, "Moreover, this Contract Magic once saved his life; if I shamelessly asked him to return that life, with Professor Dumbledore's character, do you think he would agree?"
"You want to kill him?"
Kael felt the air around him suddenly grow cold, as if countless small blades were all simultaneously aimed at him.
And it wasn't just an illusion... Even if the person before him was emaciated to mere bones, and even without a wand.
The Wampus Cat and Nundu which had followed closely behind, both let out piercing screeches, bursting through the door to rush in.
"Oh, Nundu, a truly dangerous creature." Grindelwald said mildly, "You remind me of another person I know; just like you, he's always surrounded by various fantastic beasts.
"But do you think they can protect you?"
"I think they can." Kael maintained his outward calm, stroking the necks of the Wampus Cat and Nundu, signaling them to relax and not to be nervous.
"Of course, I won't kill Professor Dumbledore, either. After all, he's my headmaster and taught me many things; I couldn't bring myself to harm him."
Kael said, "Just that I'll take him to a place far bigger than this, with sunlight, forests, vast space, and various kinds of creatures.
"But that place is cut off from the outside world, and I guarantee, even if someone turned the entire magic realm upside down, it would be impossible to find him."
"Then no one can stop me." Grindelwald said, his tone filled with supreme confidence. "Except for Albus, no one can stop me."
"As long as it makes you uncomfortable, I don't mind." Kael shrugged, "Worst case, we'll both flee there, letting you and Voldemort tear each other apart."
"Tear each other apart... That's quite harsh." Grindelwald seemed to lose interest, lying back down on the blanket, "Alright, you win, a truly terrifying threat, but I really just want to write a letter, nothing else."
"Let's hope so." Kael said.
After saying that, he prepared to leave.
"Wait."
Grindelwald called out to him again, "On your way here, you must have seen Vinda and the others."
"If you mean those who followed you sixty years ago, then yes, I have." Kael said, "Right at the entrance of the forest, there are twelve of them, all too old to function."
"It's not following, it's cooperation... Forget it, you probably don't want to hear this." Grindelwald continued, "As a token of appreciation for the parchment, let me give you some advice: When you leave later, they'll catch you and force you to disclose how you got in here."