The world was crumbling around him. Everyone he ever knew was dead on the whim of his own student. He should have known better; he should have tried harder, but now, he was paying the price for it. Naruto, Sakura, Sai, Tenzou, Kakashi - the love of his life, Kakashi - were among the many victims taken from him in his negligence.

"Sensei," came the dark, monotonous voice echoed through the rubble that was once Konoha, "where are you hiding? Didn't you want a student-teacher reunion?"

Obito swallowed as he pictured the eerie, toothy smile that Sasuke had sent him earlier - while trying to kill him, mind you. It was the smile of a killer; the smile of someone Obito had never wanted his young, misguided protégé to become.

Debris tumbled down in a tremulously, deafening roar a few blocks away, where Sasuke was inevitably standing with the creature, Zetsu who followed along behind him like an obedient underling.

Obito released a breath he was holding and stroked the hair back from Kakashi's lifeless face one more time as he settled his comrade's forehead protector over the hollow socket where the gifted Sharingan had been housed, his other hand over his returned eye, healing it into place. If he waited any longer, he'd be forced to fight and with Sasuke already containing the power of the Juubi, it was a losing battle. But Obito couldn't bring himself to let Kakashi and his team die in vain.

Although his love had never been returned, Obito had devoted his life to Kakashi after escaping Madara's clutches. He had adored Kakashi with all of his heart - regardless of what happened with Rin - and he was certain Kakashi knew that, as he had said in his last moments. There were still drying tears leaving tracks down Obito's face. Thankfully, he'd be joining him soon; he'd be joining all of them soon.

Obito had never been good at coming up with plans - that was Kakashi's job after all, especially as the next up-and-coming candidate for Hokage. But what Obito was good at, was using his brute strength and immense well of chakra to his advantage. Which led him to an idea of how to take out the Juubi jinchuuriki, or at least that bastard, Zetsu. He just needed a few minutes longer, but he didn't think he'd get that kind of time.

"Do you really intend to drag this out, Sensei? You've always been one of the most powerful shinobi I knew, but yet you couldn't even save my brother or the rest of our clan. You're nothing but the scum you preach not to be, so come out and fight me!" Sasuke cried into the darkness, clenching at Obito's heart.

He was right though. Obito had been out on a mission with the rest of his squad when it happened. He never told Sasuke that he spoke to Itachi after that, but it was that which turned Sasuke against his village and his friends.

As Obito continued to muse over the beginnings of his plan, his visible eye widened in terror as a puddle of black sprouted in front of him before blooming into a head and two beady, citrine eyes. "I found him," came its raspy, growling voice.

Not a moment later, a black orb shot through the space beside Obito's head, catching him off-guard and allowing the creature to latch onto his leg, oozing up his side to take control. He couldn't allow that, so he took a page from Kakashi's book.

Flying through a series of hand signs, Obito's hands were set alight in violet lightning before setting them on his leg and side, scorching the flesh and the symbiote. Obito clenched his teeth through the pain - he'd been through worse - and the creature screamed before jumping off and squirming away, sinking back into the ground.

The truth-seeker orb promptly turned in its tracks and made for Obito at top speed, barely missing as Obito ducked beneath its path, toppling down on his fallen friend.

"Sorry Kakashi," he uttered softly before leaping up and moving out of the way of Sasuke's attack as the Juubi jinchuuriki rushed toward him.

In mid-leap, Obito materialized a kusarigama and caught the blade coming down on him in a hail of sparks. From there, the two shinobi clashed over and over between sword and chain. Obito needed more time and Sasuke's anger would do just that; it'd give him plenty of time to prepare that jutsu.

There were no truth-seekers or reflexive uses of the Kamui in this fight. It was gritty and violent, and simply a master and student fighting by the way of the blade to the bitter end to resolve their differences in one final battle.

"I heard that you knew the clan would be killed. Is that why you fled like a coward and doomed them all and my brother?" Sasuke snarled as their blades clashed in blurs of silver and a cacophony of steel.

"I didn't flee, Sasuke," Obito grunted, retreating out of reach with a mighty leap. When he landed, he elaborated, "No one would listen to what I had to say and sent me away."

"Itachi listened to you! You and Kakashi, you were his allies and you betrayed him! You betrayed the Uchiha!"

"That was Itachi's choice. No one forced him to make it, but he did it to spare you."

Sasuke's blows began to land harder. When he slashed his blade, it came down with force enough to break a common man's arm.

"He didn't spare me a damn thing! You should have helped him! You should have made the Elders listen!"

"I'm sorry, Sasuke, but there's nothing that can be done about it now. They're dead and so is your brother."

"Which should have never happened!"

"You're right. I should have never let your brother should have never be manipulated into this, just as I should have never let you be manipulated into becoming the vessel for Madara's whims."

Sasuke stopped for a moment, backing away. His Rinnegan gaze was hard and measured on Obito, who had begun breathing more heavily long ago in their ceaseless fight.

"Sasuke, please... we can't keep fighting," Obito pleaded. "Following Madara's plan is madness. He's using you!"

"Madness? This world took away everything from me! I hardly care about Madara's plan if it means I can accomplish my own." The teen looked down at his hand, a black orb forming in the center of it as he mindlessly stared.

"Look around you!" Obito shouted, gesturing with a hand to the carnage around them. "You've destroyed everything; you've killed all of your friends! And for what? To plant a stupid tree and grow a god-complex?"

"If that's what it takes."

"You can't just do this! You should care about these things! You... You killed your best friend over this! Sasuke, you have to stop. Please... just put the sword down."

Sasuke set his eyes back on Obito. "Of course I'll stop," he murmured, his lips twitching humorlessly, stirring a feeling of deep unease in Obito's belly. "I'll stop if you can bring me back my brother!"

Immediately, Sasuke ran towards him, the black orb forming a spike through his palm as he rushed at Obito, giving him the opening he needed. He didn't want it to come to this, but Sasuke had to be stopped; Obito had to kill him.

'Please forgive me, Sasuke, for failing you,' he mournfully thought to himself and opened his other Mangekyou Sharingan eye, activating the forbidden technique that he and Kakashi had come up with.

In a swirl of chakra, everything in the area was sucked into the void. Corpses, the shambles of destroyed buildings, burning trees, dismantled Zetsus; nothing was safe from the pull of the alternate dimension.

Sasuke braced himself by digging the pike in his palm into the ground as his body was raised up by the void and sucked towards it.

But obviously, Sasuke had other ideas that didn't involve being ripped apart by what could have been called a miniature black hole.

The Juubi jinchuuriki glanced back at Obito, who was barely keeping upright with what strength he had left, his eyes bleeding down the tracks his tears had forged.

"Sasuke..." Obito called loudly, over the grumble and grind of the expansive, all-consuming version of Kamui, "let go. Let's end this together."

Sasuke scowled and ground his teeth together. "Not until I have my brother back!"

He released the spear, keeping him from flying back and allowed himself to be pulled into the path of the jutsu as he flew through a series of seals. But Obito could do nothing to evade it, not with this Kamui active.

In a flash, Sasuke was behind him, sending the pike through Obito's unguarded chest. Obito cried out in pain as Sasuke held him upright, the jutsu still active.

"You should have known you were no match for me like this," Sasuke uttered. "Your Kamui is no match for the power of the Juubi jinchuuriki."

Obito breathed hard, coughing up blood as Kamui still whirled from its owner's eyes, pulling in everything around them. "You're right. You were could have made a perceptive shinobi, Sasuke..." Obito murmured, laboriously.

Sasuke narrowed his eyes as he tried to determine what Obito was planning.

With a grin, Obito finally added, "But there's still a lot that you should have learned."

When Sasuke looked down at his hands and feet, he was covered in tree roots, holding him in place. Without further ado, Obito reversed the strange Kamui's direction and the entangled pair went flying forward, through the portal.

Sasuke broke through the roots and made a go at Obito as they fell down into the infinite abyss. The slash of his sword released a spray of blood from Obito's back before Sasuke grabbed him by the hair and turned him towards him, his hands gripping the front of Obito's vest none too gently while his ten-tailed cloak floated around him as they plummeted downward.

"Take me back! I need to cast Infinite Tsukuyomi! I need to get my brother back!" Sasuke screamed frantically into his face as Obito's eyes rolled back into his head, his chapped lips moving as though he meant to say something.

The Juubi jinchuuriki clenched his jaw and stopped them in midair, using his flight to keep them afloat, but Obito made no movement and didn't murmur a single word.

"Wake up, damn it and take me back!" Sasuke cried again, shaking the life out of his barely conscious mentor, but it was still to no avail.

Soft violet chakra poured into Obito's half-dead body as Sasuke tried to force him into awareness, his anger fully subsiding to make way for the logic he needed. It took what felt like ages, and for all Sasuke knew, it could have been. They were in a space between reality and the Kamui dimension where there was nothing but black. Eventually, Obito began to stir and Sasuke reverted back to his seriousness and rage.

"You're not getting out of this. Take me back, now," Sasuke demanded, still holding Obito up by his tattered vest and shirt with one hand after pulling away the one that had been forcing chakra into him.

"No."

"You can't win, so why not go into Tsukuyomi with the rest of the survivors? You'll get everything you wanted there; a perfect world without war."

"It's not the same, Sasuke," Obito replied, shaking his head. "It's a lie. Nothing is real there."

"But it's better than here."

Obito swallowed thickly. "I know," he said with a nod. "I know it sounds good; I've thought about it a lot too, ever since seeing one of my loved ones die years ago." Obito paused, looking up slowly to meet Sasuke's eyes, "Sasuke, don't do this. I know this isn't you; this isn't what Itachi wanted for you."

The Juubi jinchuuriki stilled for a moment, his face falling for a moment before he clenched Obito's vest tighter, making the plating under it creak as he clutched it tighter. "You have no right to say that to me."

"It's true, Sasuke. He loved you very much - he loved you more than anyone else. He'd be heartbroken seeing what you've done."

"Shut up!" Sasuke snarled, baring his teeth and clenching his jaw tightly. "You don't get to preach to me what Itachi felt. You're the one that started all this! Your negligence forced him to take on your burdens. He's dead because of you!"

"It wasn't me who killed him," Obito rasped out.

A swift punch landed on Obito's face, aptly quieting him. "If you're not going to take my side, then I'll have to make you open Kamui," Sasuke said and gazed deeply into Obito's eyes, managing to catch them before they could be shut.

He smirked triumphantly as Kamui began to open behind him, making a portal for him to walk straight through. The portal began to flicker for a moment as Obito tried to fight the hold of the opposing genjutsu, but Sasuke's Rinnegan was far more powerful than his Mangekyou Sharingan.

"At least for you, there will be no war in death. Good-bye, Obito," Sasuke murmured and released Obito to continue plummeting down as he watched Sasuke slip through the dwindling portal back into his home dimension.

Obito reached out in a last attempt to stop him, but it was too late. It was many years too late. But Sasuke was right again. At least when he died, he wouldn't have to worry about wars or resurrection; he could be with Rin and Kakashi.

He could finally go home.