~Flashback~
"Your time is almost up. So then.....after all this time has passed, how do you plan on using your remaining time?"
Echidna was seen in the Sanctuary as she was speaking to one man. As the man puts his left hand over his right arm, he began to walk away.
"Just like a parent has to let go of their child for them to grow, I think its time for Uncle Reaper to let his favorite weakling to bully to become strong. He's held onto his weakness long enough, now is the time for his growth."
~Flashback ends~
Benimaru and Xanxus were seen with the resistance members. As they arrived, Kuruno looked at the two of them. He could tell that even they had a rough time against their opponent.
"So I take it, that the weakling is fighting E.N.D at this moment."
"Yeah. Though I can't tell what the outcome might be."
"I see."
Soon Kurono unties the bandages around his arm as he made black smoke appear under his feet. Soon he made it dense enough for him to stand on as he was flying away. Seeing this, Xanxus was starting to get pissed.
"What the hell, are we on guard duty now?!"
"I don't think its that simple. I think Kurono just made an important decision and he's acting upon it. As for what that choice was, only one person can answer that."
As Benimaru said this, he looked at Spade Castle as his eyes widen with shock. Black branches could be seen forming all around the castle as he felt sinister mana from it. He could tell that things were about to be more difficult.
~With Kyoya~
"Ice Make:Cold Excalibur!!!!!"
Kyoya creates a massive great-sword out of ice and slashed at Natsu. As the etherious jumped back to avoid it, the slash launched a large cluster of ice towards Natsu as his body was frozen in a block of ice. Soon he engulfed his body in flames as he melts the ice around him.
"Fire Dragon King's Purgatory!!!!!!!"
Natsu releases an enormous amount of flames all over his body while trying to severely burn Kyoya. Seeing this, the boy quickly swung his arm to freeze the flames. Soon Kyoya jumped back as he wasn't ready to give up his advantage.
"Ice-Make:Arrows!!!!!!!"
After first crafting a bow from ice, Kyoya forms multiple arrows from both hands and fires them at high speed towards Natsu. As the arrows pierced his flesh, Natsu roars as his flames kept growing more firece.
"Vanica.....Vanica......VANICA!!!!!!!!!"
As Natsu screamed in fury, his flames grew more intense. When he stared at Kyoya, the ice mage saw nothing but undying anger in his friends eyes. Soon the etherious took a deep breath as Kyoya was gathering up a large amount of mana.
"Fire Dragon's Roar!!!!!!!!!!"
"Ice Devil's Shiver!!!!!!!"
As the two spells collided, an explosion of mana occured as they clashed. Smoke fills the air as two people were seen running at each other at full speed. When they got close to each other, they finally made their move.
"Fire Dragon's Iron Fist!!!!!!"
Natsu engulfed his fist in flames as he punched Kyoya in the gut. The boy coughed up blood as he felt his flesh getting burned. Soon he grabbed the back of Natsu's head and headbutts the boy repeatedly until blood escaped from both of their heads.
"Ice Devil's Zeroth Destruction Fist!!!!!!"
After producing the same ice that he ate from Invel's Ice-Kamui, Kyoya used his Ice-Make magic to mold the ice and created a pair of destructively powerful gauntlets with the same properties as the aforementioned spell, and uses them brutalized Natsu in flurry of punches.
After the final punch, Kyoya grabbed Natsu by his head and slams him into the ground. Afterwards, Kyoya created a giant hammer out of ice that he slammed onto the etherious with great force. As the hammer of ice was dismissed, he saw Natsu getting back up as he glared at Kyoya.
"Natsu......were you suffering all this time. While I met Ur and was training, while I came to the Clover Kingdom and joined the magic knights, while I spent time with the Black Bulls.....were you suffering all alone?"
As Kyoya said this, he quickly dodged several punches that Natsu threw at him. Soon Kyoya caught Natsu's flame engulfed fist and elbowed him in the gut. Blood escaped from the etherious' mouth as Kyoya's hand was stinging. Though Kyoya wasn't angry. If anything, he felt nothing but guilt.
"Vanica!!!!!!!!!!"
Natsu slams his fist into the ground and creates multiple fire pillars from the ground and onto Kyoya. As the boy was trapped in the flames, he glared at Natsu.
"I made a promise.....I will stop you!!!!!!"
As Kyoya spread out his arms, he created a circular barrier of ice around Natsu. Afterwards, he slams his fist into his right palm as a spiky ice shard formed in the center. Natsu felt his own blood dripping onto his body. Soon he began to punch through the barrier of ice. When he escaped, both himself and Kyoya were charging at each other. When they did, a vague image entered their minds as they clenched their fists.
"I'LL KILL YOU!!!!!!"
"I'll save you, Natsu!!!!!!!"
As their fists collided, fire and ice could be seen clashing against each other. The more that their fists collided, the larger and more powerful the explosion of mana was.
~Meanwhile~
As Kurono was flying over to Kyoya's location, he saw the explosions of mana clashing. When he looked at it, he could see parts of the Spade Castle beginning to crumble as he thought to himself.
"If this keeps up, the two weaklings could both end up dying AND destroy the castle where everyone is fighting, practically killing them all."
While Kurono thought of this, he puts his left hand over his mouth as he coughs up blood. When he did, he remembered what a certain witch told him.
~Flashback~
"That new arm of yours is dangerous, you know. Keep using, and your very insides might melt from the heat or your lungs might stop working due to the smoke."
Echidna was standing before the last Child of Sin, the Child of Lust. As she looked at Kurono, she saw the man wrapping bandages around his arm.
"Have I ever told you this? The reason why I bully the weak...is because I want them to remember their weakness."
"What are you talking about, Kurono?"
"Take the royals of the Clover Kingdom. They're born strong, barely even bother to hone their craft, all because they never experienced weakness. When they lose, they don't get back up and they break easily. But weaklings....they always held their weakness with pride as they choose not to stay weak and it makes bullying them fun. Because no matter how much you knock them down....they refuse to break and do nothing. Their weakness is what gave them their strength. Their weakness is something precious that most people will take for granted."
~Flashback ends~
Kurono was soon at the battlefield as he saw both Natsu and Kyoya facing off. The two boys were charging their fists with a large amount of magical power. But Kurono noticed something, while Natsu's mana was unyielding and suffocating, Kyoya's felt restrained.
"I'LL KILL YOU, VANICA!!!!!!"
"I'll SAVE YOU NATSU!!!!!!"
The two boys charged at each other as they both threw their fists. As this happened, Kurono flew down as he had to stop this. This one clash, he could tell that if its momentum isn't stopped...everyone in the castle would die.
"I already didn't have time to begin with. I wanted to bully this weakling more. I made myself something he feared, so that when he was no longer afraid of me....he would be prepared to conquer his biggest fear. His own curse and Vanica."
Blood splattered onto the snowy ground. As Kyoya looked in front of him, he saw his arm going through someone's torso as Natsu arm burned through the man's chest. When Kyoya looked up, he saw Kurono's face in front of him.
"I made it....good. Anymore strikes like that....and the weaklings inside would've died as well."
"Kurono! What are you doing here?!"
"I wanted to save the weaklings. Of course, that counts you two as well."
Suddenly black smoke manifested around Natsu and trapped him in a sphere of smoke. While this happened, Kurono looked towards Kyoya.
"It must be a shock for you. For your best friend to be your enemy. For your torturer to be an ally even for a moment. Though....Kyoya, there's more than one way to save someone. Death is also a natural part of life. If you live while fearing it, you'll begin to fear everyday of your life. But you've been with Uncle Reaper since day one....."
"Stop speaking Kurono!!!! We need to get you to a recovery ma-"
"Don't hold back, Kyoya Fullbuster. Do you want your friend to continue to live on in pain? Or will you give him death and release him from his suffering? You know.....I envy the weak. The weak forms bonds easier with other weaklings after all.....hold onto your weakness....your precious flaws....its those little things that have a big impact on your life."
Kurono began to cough up more blood. To be honest, he already knew he had limited time. That's why he spent his time doing whatever he wanted. But, he did have one regret. He wished he was weak and had comrades to grow strong with. Now....he's just going to die alone, with his death not having any weight behind it.
"Thank you.....Uncle Reaper. You always forced me to push pass my limits, even though your methods were cruel. But in the end...it helped shape who I am."
Kurono's eyes became wide when he heard this. As he looked at Kyoya, he saw the boy have a look of sympathy in his eyes. Soon a small smile appeared on his face as his eyes were slowly closing.
"Weakness. It has many forms. It has many meanings behind it, just like death. They're both something that every human experience. Though they both lead to limitless possibilities. Just as ones weakness can give them strength........"
The sphere made of smoke slowly began to disappear. As Kurono was looking at Kyoya, he felt a tremendous amount of mana coming from Kyoya as the boy's hair was slowly turning white. Soon he closed his eyes as he thought to himself.
".....the death of one thing, can give birth to another. The death of Kurono, will give birth to Kyoya's unwavering resolve."
Natsu soon escapes from the sphere made of smoke. However, when he did, he saw a coffin made of ice as Kyoya was standing before him. While Kyoya was releasing a large amount of mana, he said one thing.
"Rest in peace, Kurono. As for me.......i'll save Natsu, even if it means I have to get my hands dirty. I was saving this for later, but I know I can't save anyone if I half-ass my effort."
Soon a large gust of cold air was felt as Natsu looked at Kyoya. When he looked forward, he saw the boy has undergone a change. His hair was white as snow. Parts of his shoulders, legs, and arms were covered in ice made from his Devil Slayer magic as he also held a sword made of ice in his right hand.
"I took a page out of Invel and Yuno's book. I assimilated a large portion of the ice from my Devil Slayer Magic into my body, whilst using my Ice-Make Magic to mold it on the outside. The name of this spell is.........."
"Ice-Make:Ice Devil's Kamui."
The time for restraint and doubt is over as Kyoya unleashes a brand new strength. The battle between Devil Slayer and Etherious is growing more fierce.