"I make the first move."
(Third Person POV)
Kurama let loose another earth shaking roar, that tossed stone, wood and ponies flying, as he charged for the castle his starting push decimating large portions of road and buildings that were directly behind him, while his nine furiously whipping tails destroyed every building in direct vicinity to him. He flew towards Canterlot Castle, house sized fist raised, ready to take a chunk out of the majestic home of the solar princess.
But she had other ideas.
Just before Kurama made contact, Celestia reacted. A bright yellow shield dome surrounded the castle, protecting it from the coming demon spirit. He slammed into the shield, the point where fist met energy rippled before bouncing the mighty Nine Tails flying away (unfortunately into an apartment block).
Ponies screamed and yelled, running around the city in panic as the monster tore apart the building he was in while trying to pull himself out of it. His immense weight caused anything he tried to pull himself up with to crumble and fall, so after a short tussle trying to get free Kurama gave up, turning over, curling up and then spreading his arms and tails out with a roar of rage, destroying the stone building completely (sending more non-pegasi ponies flying through the air in the process).
Princess Celestia lowered the shield around the castle and took flight, glowing majestically as she climbed through the smoke filled night sky. She glared down at the orange menace with malice, wanting nothing more than to simply rain down a storm of magic bolts upon him for the destruction he had caused and the ponies he had killed with his mere arrival and for risking the lives of one of her dearest friends and her newborn foal. But never let it be said she wasn't a patient and forgiving ruler.
"You have transgressed against Canterlot and its citizens." Celestia proclaimed, her old royal voice finding its way to the surface again. "For that I should just destroy you right now. However I am willing to offer you a chance to leave now and never return, if you do not do so and continue to put my pony's lives at risk I will be forced to end your life right here."
For a moment there was silence between the two, filled only with the screams of the city around them. Then the sound of low, malicious laughter filled the air, gradually growing in volume until it was all that could be heard for kilometres around.
"You'll destroy me?" Kurama chuckled after his mad laughter had died down. "DO YOU TRULY BELIEVE THAT YOU SCARE ME?"
With that Kurama attacked. First he stared making strange signs with his massive hands, he then opened his fanged maw wide and with a shout of:
"FIRE STYLE:BLAST BURN!"
A massive torrent of brilliant red fire erupted from his mouth, heading straight for Celestia spreading wide as it did so. The solar princess gasped and contained herself in a shield bubble, but she could still feel the intense heat through it as she and the shield were consumed by the flames.
Kurama kept up the attack for a short while eventually letting the torrent subside and burn out. He wasn't even aware he could use jutsu or even had chakra. He had just assumed that his only offensive capabilities were his teeth, claws and tails, the use of that attack was on a form of instinct. His body knew what it could do and he supposed it just took the initiative.
From the smoke of the flames, burst Celestia. Her eyes aglow with fury and power, she let out a scream of effort and sent a beam of raw magic straight at the Demon Fox. It collided with his chest and exploded, consuming the area with even more smoke. Kurama was getting really bored of smoke.
He leaped from the smoke just as the princess had, his huge arm swung back, his fist closed and with that his arm swung forward again, knocking the Sun Princess back through the air and straight into Canterlot Castle. She smashed through the glass doors of the balcony she had been standing on less than five minuets before. She was able to stop herself before she crashed into a hospital bed, skidding along the floor digging in her hooves as she went to slow herself.
"Princess!" Day Break exclaimed as the solar deity came flying through.
"Day Break! What are you doing?!" Celestia exclaimed as she watched the new mother slot her helmet down on her head, her bright red mane springing out to from the plume.
"I'm ready to go Princess Celestia. Just say the word and I'll join the rest of the guard regiment who have just begun attacking the beast." Secretly Celestia was deeply relieved that the guard had engaged, if they hadn't the fox probably would have gone after her and destroyed the castle in the process, still.
"No I can't let you go out there, not now." Celestia said as she slowly rose from her crouch.
"What! Why?"
"Day Break, think of Sunset. You need to be with her, I'll defeat this monster."
"And how do you plan to do that?!" Day Break shouted. Normally she wouldn't have dreamed about shouting at the leader of Equestria, despite there close friendship, but in this case she couldn't help herself. Her outburst woke the filly sleeping in the cot beside the hospital bed. She bawled her little eyes out even as her mother held her and offered her sweet words of comfort. "How do you plan to defeat it?" she asked again quieter this time.
"Do you doubt my abilities?" the Sun Goddess asked sternly.
The guards mare sighed in relief as her foal began to quieten down "I do not. But princess, with respect, I think he's more than even you can handle." Day Break said solemnly.
"He?"
"You can hear it in the voice." the mare dead-panned, before becoming serious again. "I do not believe you will be able to defeat him." Day Break repeated looking at the tips of Celestia's wings, which were slightly burned. "That fox has enough power to harm you through your shield and can withstand your attacks easily."
"Do you have any other ideas?" Celestia asked warily, she was afraid that she already knew the answer.
"We need to seal him, within somepony." Day Break clarified, before going through with an explanation. "I will gather all of my magic and use it to construct an Eight Sign Sealing formula and use that to lock him away."
"ALL of your magic!! But Day Break that'll...that will kill you! The seal won't work on you if you're dying! Who would you seal it in if not yourself?" Celestia finished her slight rant with a small hiccup like sound which was actually her trying to hold in her tears. This was one of her close companions and she was saying that she was going to kill herself in an attempt to seal this beast, a seal that would only work if the conditions were perfect. A powerful sealer, a strong willed host and the target had to be still and restrained. "I can't take it even my body couldn't take both mine and its power."
"I know. My plan was never for me or you to carry it." Day Break said, her calmness the opposite of the princess' panic
"Then who?!"
Day Break held up the little filly, who was asleep once again in her mother's cradling foreleg. Celestia stared blankly for a moment, her jaw hanging loose on its hinges. While it was true that foals were better choices for hosts, as there bodies were more accepting of external energies, she couldn't believe that Day Break was suggesting her own daughter should be the one who would become the monster's prison.
"No. Day that is your daughter, you can't..."
"I KNOW!" Day Break cut her ruler off. "I know."
"Why? Why subject her to such pain, losing her mother to become a living asylum for a monster?" The pain in Celestia's voice told Day that she had been defeated, but she still clung to the chance that she could change the guard-mare's mind.
"Because I believe that she can handle it. Her path will be a hard one and I feel tortured knowing that I'm setting her on this path without her consent. But I believe that if she can fight through these hardships, she will become a stronger pony than I could ever hope to be." Day Break finished her speech by planting a kiss on her little horn. "I know it's a lot to ask but I need you to take care of her for me. Guide her, teach her right from wrong, make sure she lives a good life - but not a spoiled one mind you." she finished with a cheeky smile. "Will you do that for me?"
Celestia sighed and wiped away a tear. "I will, you have my word."
Day Break smiled, she knew the princess would put her personal feelings aside for the good of her kingdom. "Thank you." She said simply. Now directing her attention back to the raging beast outside. "I'll also need a distraction and for you to hold him down when the time comes."
"Take your time, I need to pay that massive mutt back for knocking me through the castle." the Princess of Equestria smirked as she walked to the balcony. Before leaping out she turned to the guards-mare, who was already attaching a foal carrier to her back. "May we meet again soon in another life my dear friend."
"Not too soon, thou stillst has yet to experience the joys of pregnancy." Day Break giggled, openly taking the piss now.
"We'll see." With that the Sun Princess leapt from the balcony.