Madara Uchiha was a little lost.
He had clawed his way back from the underworld to realize the Eye of the Moon Plan, only to learn, just as he was about to begin, that Black Zetsu had been lying to him the entire time.
It was an unbearable betrayal.
Black Zetsu, however, paid him no mind. It simply ignored him, focusing on its conversation with Naruto Uzumaki, as if they were the true allies. "If you are also afraid of the people from beyond the heavens, then lend your chakra to Mother for now. Only when Mother gathers all the chakra can she defeat them..."
"But she couldn't even beat her own two sons..." Naruto was almost too embarrassed to point out the flaw in Black Zetsu's logic. Forget her sons, she couldn't even beat the reincarnations of her two grandsons.
Black Zetsu explained sinisterly, "That's because Mother loved them too much... What mother in the world would want to harm her own children?"
"Do you even believe that yourself?" the young Hokage retorted. "Stop dreaming, Black Zetsu. You don't have a choice here... If you don't go along with my plan, you can all just wait to die! In a few years, the outsiders will arrive and throw this world into chaos!"
In fact, the time might be even shorter. No one could guess their thoughts or movements. Perhaps as Naruto's own power grew, the outsiders would suddenly appear to harvest his chakra, or even the power of the entire ninja world.
"Heh heh heh..." Black Zetsu gave a sinister laugh. "Then let's unify this ninja world first, rescue Mother from the moon, and then we can discuss who will lead the resistance against those enemies from beyond the heavens!"
"...What about Madara Uchiha?" Naruto asked, looking at Madara.
This guy was a problem. Should he kill him outright? But his power could be a major asset, and the Rinnegan was rare. But if he didn't kill him, Madara was completely immune to "Talk no Jutsu." Even Hashirama Senju had a hard time convincing him of anything.
What a massive headache.
"Since my plan has already been exposed..." Black Zetsu glanced at Madara and said coldly, "just kill him. Why keep him around?"
A truly ruthless suggestion. Since Black Zetsu had already betrayed Madara, it didn't want another powerful enemy hunting it down. And with its original plan in tatters, it decided to see if what Naruto Uzumaki said was true.
If Naruto was telling the truth, it would find a way to persuade Kaguya that resisting the outsiders was the most important thing. If Naruto was lying, it would simply disappear for another thousand years and wait for a new opportunity to revive its mother.
Where there is light, darkness will surely follow. It only needed to wait patiently, and eventually, some people would willingly fall into darkness.
"Let him be," Naruto said slowly. "After all, his power can be used against our enemies. The power of the Rinnegan isn't common, and the Uchiha clan also needs to procreate..."
Black Zetsu: "..."
Madara Uchiha: "..."
After a moment, Naruto continued, "Madara Uchiha, your Eye of the Moon Plan was a lie. Why not try unifying the ninja world to see if that can bring true peace? The First Hokage has already approved my plan!"
"..." Madara's Rinnegan shifted slightly. He asked in a grim voice, "Oh? Where is Hashirama?"
"The First Hokage is currently in the Land of Water," Naruto confirmed. "If you agree to my plan, then go to the Stone Village and help us deal with that old man Ōnoki!"
"Hmph!" Madara snorted indignantly.
Decades of planning, all for nothing. All he wanted was to find a quiet place or maybe talk with Hashirama. Did this brat not understand simple requests? Did he really think he had surrendered? Did this little twerp Naruto not know who he was? Was Madara Uchiha someone who surrenders?
Unexpectedly, Naruto added, "If the Third Tsuchikage takes the initiative to attack the Land of Rain or the Land of Waterfalls, the First Hokage will lead troops to the coast of the Land of Earth and strike the Stone Village and the Daimyo's mansion directly..."
"...So that fool Hashirama is going too?" Madara slowly clenched his fist. A contemptuous smile touched his lips. "Then I'll go test that little brat Ōnoki and see how much he's grown!"
-----
Land of Rain. Inside the Rain Village.
The Konoha forces led by Jiraiya had already infiltrated the Rain Village and secured key terrain. They were now in a standoff with the Stone Village's army, while the Sand Village's forces applied pressure from the side.
Overnight, the Land of Rain seemed to have returned to the days of the Second Great Ninja War, once again becoming a battlefield for the great nations. The Rain Village itself had completely become Konoha's forward command center.
Jiraiya glanced at Shikaku Nara and sighed. "Are we really doing this? Going to war with the Stone Village? Once this starts, it'll be another Great Ninja War..."
"It will also be the last," Shikaku Nara said softly, taking a sip of tea. "Our original plan was to occupy the Land of Rain to cut off the Land of Earth. We just didn't expect the Third Tsuchikage, at his age, to be so bold."
"His nation is on the brink of destruction. Of course he's not going to give up without a fight," Jiraiya said, tapping the map on the table. "What is that brat Naruto thinking? Konoha has conquered two great nations in less than a year!"
"The Fifth Hokage has the power to unify the world on his own. He isn't going to waste time on these things..." Shikaku put down his teacup and intercepted a strange bird, removing the note from its leg. He chuckled. "It seems the Sand forces are in position."
The Sand ninja were designated as a surprise attack force. While the Konoha and Stone armies were locked in a standoff, the Sand would strike the Stone's rear, destroying their supplies and reinforcements.
Shikaku smiled and wrote an order. "Let the Sand Village initiate the start of the war... As for the reason, we'll use the Stone Village's cooperation with the Akatsuki and their harboring of Madara Uchiha."
"I think you should change that reason."
A kunai marked with the Uchiha fan suddenly embedded itself in the table.
Just as Shikaku looked up in surprise, Sasuke Uchiha appeared, a long-haired man in tow. "Naruto sent me with backup," Sasuke said softly. "Do I need to make an introduction?"
Seeing the man beside Sasuke, the pen fell from Shikaku's hand. Jiraiya's jaw nearly hit the floor. "What the hell... Is that...?"
"Yes, Madara Uchiha," Sasuke confirmed, rubbing his forehead. "Orders from that guy Naruto. When Madara Uchiha arrives at the front lines, we can send an envoy to the Third Tsuchikage to announce that the Fourth Great Ninja War... has begun."
Shikaku Nara: "..."
Jiraiya: "..."
"Has Konoha fallen to this level?" Madara Uchiha said, looking at everyone present with displeasure. "Besides that brat Naruto, none of you are much to look at. Assemble your troops! Today, you can announce the Stone Village's defeat!"
-----
Bonus:
At the Valley of the End.
Madara looked at Black Zetsu and said: "Zetsu is an honored guest, while I, Madara, am a prisoner. Why not speak a word for my sake?"
Black Zetsu nodded.
When Naruto Uzumaki came up, Madara Uchiha cried out: "The Hokage's only trouble is Madara; today, Madara submits! With Naruto as Hokage and Madara as his assistant, the world will not be difficult to pacify."
Naruto Uzumaki looked back at Black Zetsu. "What do you think?"
Black Zetsu replied: "Have you not seen the case of the First Hokage, Senju Hashirama?"
Madara looked back at Black Zetsu and said: "You black thing! Have you forgotten the matter of the Naka Shrine?"
Naruto thought about it. The First Hokage had treated Madara Uchiha with great generosity, yet Madara did not think of being loyal to Hashirama, but instead repeatedly coveted the position of Hokage.
Just as he was about to give the order for execution, a person nearby shouted: "Naruto, stay your hand!"
When everyone looked, it was Senju Hashirama.
To know what happens next, you'll have to wait until I've thought of it.
—From Idle Chatter: The Execution of Madara Uchiha at the Valley of the End