A replacement

The Land of Fire, in a corner no Sensory Ninjutsu could detect.

Deep underground, a Cave lay so deathly quiet that only water dripping through cracks in the rock could be heard.

After sleeping for who knew how long, Obito's eyes snapped open. Cold stone still filled his vision.

Ever since he had been rescued from beneath the collapsed boulder, his life had fallen into the gap between life and death.

There was no day or night here, no changing seasons. There was only a withered old man who called himself "Madara Uchiha," and a group of pale-skinned artificial humans who appeared and vanished like ghosts.

"Kakashi... Rin..."

Obito struggled to sit up on the stone bed. The right half of his body, reconstructed with white Zetsu cells, pulled stiffly with every movement.

He clenched his fists hard, feeling his nails dig painfully into his palms. It was the only proof he had that he was still alive.

"I'll come back. Just wait for me."

He struggled off the bed and began his tedious, painful rehabilitation exercises inside the cramped Cave.

One lap, two laps... He dragged his heavy body along at a slow run, sweat sliding down his half-disfigured face and dripping onto the cold stone.

In the darkness, where all sense of time was lost, his longing for Kakashi and Rin was the last thread holding his sanity together.

Deeper in the Cave, a white-haired, aged figure sat motionless before the Demonic Statue of the Outer Path, watching the struggling boy coldly through his Sharingan.

There was no pity in Madara Uchiha's gaze, only appraisal.

"What a pure-hearted child." His voice was low and hoarse. "Such is often the fate of the Uchiha. To find love, then lose it."

This was the finest nourishment for awakening the Mangekyō Sharingan.

Madara Uchiha raised an arm like dead wood and waved lightly toward the shadows, a satisfied smile curling his lips.

"His body has nearly recovered. It's time to begin the next stage of the plan."

At Madara Uchiha's command, a White Zetsu with a spiral-patterned face silently approached Obito.

Obito stopped and looked at the artificial human who called himself Tobi, a little puzzled.

"Obito, Obito! I just got back from a little trip around Konoha! I saw that Kakashi and Rin Nohara you're always talking about."

Tobi walked with comical steps, his tone light, as though he were telling an amusing story.

"Kakashi... and Rin?" Obito's eyes lit up at once. He grabbed Tobi's shoulders eagerly. "How are they? Are they hurt? Have they... been thinking about me?"

"Hmm, they looked pretty good." Tobi shook his head theatrically. "Training, missions, everyday life. Their days are nice and full."

"Really... Thank goodness." Obito let out a relieved breath, his shoulders dropping as a faint, grateful smile tugged at his lips. "Of course. With Kakashi there, Rin must be well protected..."

"But..." Tobi drew out the word.

Obito's heart tightened. "But what?"

"Seems some guy called 'Asami Ri' has taken your place on the team." Tobi spoke with feigned casualness. "Kakashi looked pretty happy sparring with him. Minato-sensei seems to think highly of him, too. As for Rin Nohara..." He tilted his head. "She's happy, too."

"Happy?" Obito froze.

"That's right." Tobi's voice was cheerful, yet it scraped slowly across his heart like a dull blade. "The one by their side... isn't you anymore."

Obito's throat tightened.

"They won't forget me!" he growled in denial, but his words seemed to fall into a hollow void, their echo pitifully faint.

He forced his weak right leg to support him and staggered to his feet, ignoring Tobi's mockery. He resumed his rehabilitation with almost crazed intensity, each step thudding against the stone floor.

Though he said he did not believe it, an unfamiliar terror and urgency sank their fangs into Obito's heart like a venomous snake.

He told himself over and over: Kakashi and Rin aren't like that. Yet Tobi's tone kept replaying in his mind, along with Kakashi's profile, Rin's smile... and another figure standing between them.

His breathing grew rapid, anxiety and unease spreading through his eyes like a smoldering fire.

In the shadows, Madara Uchiha closed his eyes as though listening to a pleasing rhythm. The shadows deep in the Cave writhed faintly, as if the darkness itself had come alive.

"Black Zetsu."

"Here." A viscous voice sounded from behind the stone seat, and black liquid silently welled out.

"It's time for Kirigakure... to make its move." Madara Uchiha's voice was calm. "The Three-Tails should return to where it belongs, too."

"Understood."

Black Zetsu gave a chilling chuckle, then silently slipped into a crack in the rock and disappeared into the darkness.

Madara Uchiha turned to look at Obito Uchiha, who was training frantically in the distance, drenched in sweat.

In his eyes, the boy's efforts were nothing more than the illusion of a dying struggle.

"Since this world is filled with emptiness that can never be filled, since 'love' will ultimately become a curse of despair..."

His memories of Hashirama flashed before his eyes again: their first meeting, coming to understand one another, founding Konoha side by side, and finally their bitter split.

Every memory was as clear as if it had happened yesterday, but after that night, the rift between him and Hashirama could never be mended. Ideals and reality, convictions and paths had been torn apart completely, until all that remained was to turn their blades on each other.

He had tried to decide the fate of the Shinobi World through force. He had lost, yet in a sense, he had won as well. Hashirama was dead, while he had grown decrepit, clinging to life deep underground.

There was no longer any room for him beneath the sun, so he could only place his hopes in the shadows, advancing his plan through subtler, more drawn-out means.

"Hashirama, your 'will of fire' is nothing but an empty dream in the end. Just watch. With my own hands, I will bury this shattered old era and create a perfect world with nothing but peace, nothing but 'love.'"

Madara Uchiha's eyes gleamed as he recalled the records on the stone tablet.

"Infinite Tsukuyomi... is humanity's ultimate salvation. Everyone will have everything they desire. No pain, no sorrow."

Inside the Cave, the sound of Obito crashing heavily to the ground rang out once more. Panting, he stubbornly climbed back to his feet yet again.

Every step he took forward was, in truth, another step toward the abyss called "despair."