At the core of it, things were indeed rather simple. Sunny hated the Black Knight enough to do his due diligence and thus spent an incredible amount of time studying it. He was so motivated to kill the creature that had hurt him that he had even gone so far as to settle in the same old cathedral as the devil.
As a result, Sunny had become a singular expert on everything having to do with the Black Knight. He knew his strengths, he knew his weaknesses, the patterns of his behavior…
And, most importantly, he knew what type of unnatural powers the devil possessed.
Unlike Nightmare Creatures of lower ranks, devils had access to bizarre and harrowing powers that were akin to the Aspect Abilities of the Awakened. That was what made them so dangerous, and that was why the fact that Sunny had learned the Black Knight's power was so vital.
Unlike the Spire Messenger, whom they had to fight blind, the cohort was going to go into battle with the Fallen Devil fully aware of what they would face. As such, they could plan, come up with strategies, and make preparations.
Knowing your enemy was half the victory.
The second half was knowing yourself.
The smile disappeared from Sunny's face. Leaning forward, he said:
"The Black Knight is truly a living nightmare. He is as strong, fast, and indestructible as you would imagine a Fallen Devil to be. I've seen countless creatures fall to his sword — no matter their shape, size, rank, or class. He is just too powerful."
Effie giggled.
"You're not really making your case, Sunny. You know that, right?"
He glanced at her and grinned.
"That's not even the worst part. What really makes him an incarnation of death is not his astonishing might, but the darkness that lives in the grand hall of the cathedral and seems to obey him. When wrapped in that darkness, the Black Knight can move fast, unseen, and without making a single sound. His physical traits are vastly enhanced, turning him into an unstoppable engine of slaughter."
Sunny grimaced.
"What's more, any damage done to him is instantly repaired as long as he is surrounded by the darkness. Inside of it, he is basically immortal."
The members of the cohort glanced at each other with dubious expressions. Only Changing Star remained indifferent.
A tentative smile appeared on Sunny's face. Turning to Nephis, he said:
"But that is where you come in, Neph. With your radiant light, that darkness will vanish. Your flames can strip the bastard of his greatest weapon. Without his dark power, the Black Knight is nothing more than a powerful abomination. He will be only slightly more dangerous than a demon of the same rank."
Caster stared at him and said, his voice flat:
"You say it as though a Fallen Demon is an easy enemy to face."
Sunny shook his head.
"No, I am not saying that. I fully understand how hard that fight will be. In fact, I understand it better than any of you. The truth of the matter is that even with the Dawn Shard, our weapons won't be able to wound him. Not because his flesh is too tough, but because he is covered in heavy armor from head to toe. I am not even sure that there is any flesh beneath it, to be honest.
There is only one chink in his armor, and that is the visor of the helmet."
The Black Knight had two burning red embers instead of eyes, so Sunny didn't even know if the bastard had a face.
Kai shifted a little and said with uncertainty:
"So the only way to kill him is to hit the crack of the visor? I am… I am not sure that this is possible. On a fixed target, sure. But on a moving one, especially one that fast and deadly… I can't promise that I'll manage that."
The others nodded, expressing their agreement.
Sunny smiled.
"Ah, yes. That would indeed be tough. Luckily, we don't have to."
He paused for a moment, and then revealed the secret that had taken him a long, long time to uncover:
"The truth is, the visor is a trap. It seems like a weak spot, but it's not. The real weakness of the Black Knight is not even protected by the armor."
A dark expression appeared on his face.
"It's his sword."
Indeed, after observing the devil for months, Sunny had come to the conclusion that the secret to destroying the damned thing hid not in finding a way to pierce the bastard's armor, but in destroying his terrifying greatsword.
By watching the Black Knight fight against countless Nightmare Creatures, Sunny had been able to notice a curious pattern. Just like the members of the cohort, the abominations who wandered into the cathedral tended to instinctively go for the eyes of its guardian. But the bastard didn't care about those attacks at all.
He did, however, tend to protect his sword against most powerful blows, going so far as to receive them with his body instead of blocking or deflecting them with the obliterating black blade. As if wary of any damage being done to it.
By focusing on this pattern, Sunny had confirmed that the sword was indeed the only thing that the Fallen Devil seemed to be reluctant to put in harm's way.
It was his true weakness.
Nephis tilted her head slightly and echoed his words:
"...His sword?"
Sunny nodded.
"Yes. If we want to kill the Black Knight, we will have to destroy his greatsword. That is the only way."
Effie blinked a couple of times, then glared at him in outrage.
"Is that what you call not being protected by the armor? Of course it's not protected by the armor! Because it's even tougher than the armor, you doofus!"
She shook her head.
"How are we supposed to break a sword fit to be wielded by a Fallen Devil? Huh?"
Sunny smiled.
"Oh, you don't have to. In fact, I insist that you don't. You are there to help me, but no one can kill that bastard except for me. No one, you understand? So, your task will be to hold that fiend off. Leave the sword to me."
The huntress scoffed.
"That's not really an answer. If none of us is strong enough to even come close to breaking such a powerful armament, how are you going to destroy it?"
Sunny stared at her for a bit, then shrugged.
"I am not going to destroy it. Do I look like someone who can destroy it? No, I don't. And I can't."
A dark grin appeared on his lips.
"...But the Stone Saint? I am willing to bet that she can."
She was able to slaughter two Fallen Beasts before even becoming his Shadow. Now that Sunny's own shadow had grown strong with almost a thousand fragments fueling it with power, there were very few things in the Dark City that the Saint couldn't destroy with its help.
So yes, he was willing to bet that she would be able to break the sword of the Black Knight.
In fact, he was going to bet his life on it.