The night was shattered as a giant explosion rocked the Earth and the sky. In the darkness, a giant monster with almost wood-like skin and a single red-ringed eye roared to the heavens. It was a beast as ancient as the world itself, and its ten long tails drove home the name of the creature: the ten-tailed Juubi.
The ninja alliance had spent days fighting not just this beast, but also armies of the undead and Zetsu. They were all battered, broken, and tired. Many had lost their lives, and with no time to mourn, some fell into sorrow and grief. But it was about to get much worse: the beast reared back its head, and a spinning ball of gigantic proportions began to form in its colossal maw. In the distance, the HQ of the ninja alliance was right in the line of fire. The tired and broken ninjas tried their best to stop the beast from firing, but they were too late.
At the HQ of the ninja alliance, a single man ran from the premises, heading straight toward the beast. Then the creature's giant maw snapped shut around the ball of chakra contained inside until it opened wide, and a blast of condensed energy shot forth, heading straight for him. The man held up his hands as strings of chakra swung from his fingers, and black inky tendrils snaked down his arms.
The inky black soon formed a circuit-like pattern, and smoke seeped out of them, coalescing into four strangely shaped swords, all held up by the chakra strings. The swords were quite famous; they were all copies of Samehada. As the blast drew near, more swords were created until a large wall of them, all held up by chakra strings, was ready to block the incoming blast. All the energy and power from the beast's attack were absorbed into the wall of blades, and when the blast finally subsided, the wall went poof in a cloud of smoke. The smoke seemed to coalesce and seep back into the skin of the person who created the wall of blades. The black inky circuits grew and thickened, almost covering his entire body, turning his skin black while his golden hair slowly began to turn gray.
Slowly, the gray-haired, black-skinned man sighed in relief, beginning to cough up large amounts of steam as if his entire body were boiling from the inside out. As he composed himself, he looked into the distance. The fight was still going strong, and the beast seemed more contained. He was too tired to move when an orange figure rushed toward him.
As the figure drew closer, it became clear that it was a girl around the age of 17, with bright golden hair and sparkling blue eyes. She rushed up to him, fussing over his reckless actions. "Why would you do that, big brother? You could have died!" she yelled, her features marred by concern and terror.
He looked at her for a long moment and said in a gruff, hoarse tone, "Could anyone else have saved them?" She stared into his eyes, then slowly looked back toward the large building. Shaking her head, she replied, "No."
The silence between the two felt almost foreign. In the past, the girl would talk endlessly about her day, sharing the exciting events from her missions, her favorite ramen toppings, and the strange flavors she had convinced others to make for her. She would complain about how clueless her teammates were and the lateness of her Cyclops sensei. But now, she couldn't find the words to chastise him for doing something she would have done herself. She would do anything for a friend; how could she ask her only family member to act any differently?
As they sat in silence, the gray-haired man looked up at her and said, "You better head back to the fight. I can't do anything now; I'm burning from the inside out." The girl looked like she was going to protest, but the sounds of explosions and screams in the distance shifted her focus to a different group of people in danger. She began to rush toward that location.
As he watched the girl disappear into the distance, he noticed the living mountain rearing back again. He sighed, not thinking he would leave this battlefield alive. The beast getting loose only confirmed it. Another attack, a blast of greater magnitude, was bound to follow. Soon, four ninjas wearing masks painted with animal faces appeared behind him. But before they could lift him and take him to a medical center for healing, he yelled, "Don't bother!" His hoarse laughter echoed in the ravine before him. "I'm not leaving this battlefield alive anyway."
The finality in his voice made the masked shinobi take a step back. "Go evacuate that damn encampment already! If that thing breathes fire again, I probably won't be around to stop it after the next shot." Realizing the dire situation, the four sped off in a blur, invisible to anyone not as well-trained as the gray-haired man.
"Well, Shirou, you really have done it this time," he thought, choking on laughter and hot tears streaming down his face. He knew this would be his final fight—if you could even call it that. As he continued to stare ahead, the orange girl, Naroko, was all he cared to see. His little sister had grown so much over the past few years, and he was so proud of her.
His sharp eyes caught sight of the giant snails, lashing and rising. Smiling, he looked forward into the eye of his demise; this would be his last stand, his final act of protection. The girl sensed something was wrong and looked back toward where her brother was. With her enhanced vision, she could barely see him rising to his feet, and overwhelming terror washed over her when she saw Samehada forming from the smoke that emitted from his body. Instead of a wall like before, he held one sword in each hand. It was clear this was all he could do at this point.
He didn't lack chakra; in fact, he had too much. Most of his chakra coils were burning, overfilled to the point that he felt bloated, as if he was going to explode. He had been pumping most of it into his memorized blade technique, a combination of sealing techniques and ninjutsu. As the girl looked back toward the beast, she saw an even larger ball of energy than before. In a panic, she ran back toward her last family member. Even if he wasn't her blood relative, she saw him smile and mouth his final words: "I love you, little sis. I'm so proud."
The world seemed to slow down for her as the flame-like blast shot past, barely licking at her skin. Staring in horror and devastation, she watched as her last family member took his swords and met the blast head-on. The light was so bright that she could barely make out his figure blocking the attack. After agonizing seconds that felt like hours, the blast finally stopped, and for a brief moment, her brother seemed fine. Then his inky black skin pulled under him, beginning to devour the ground around him. A black dome formed above him, then compressed into a miniature black hole—and with a pop, he was gone.
In the silence that followed, as the girl stared at the crater, all anyone could hear was a silent whisper: "Shirou." Then, a heart-wrenching scream: "Shirou!"