A/N: I haven't written anything for Naruto yet, but this idea came to me and won't let go.
Also, I don't own Naruto.
Jiraiya was an infamously powerful and skilled shinobi. One of the three legendary Sannin. Spymaster, veteran of decades of war, the most knowledgeable seal-master the world had seen since the fall of the Uzumaki, unmatched in the arts of subterfuge. All of this meant that there were few things in this world that could possibly get the drop on him or surprise him.
"Hello Jiraiya, want to save the world?"
His traitorous former teammate appearing out of nowhere a foot away from his face was one of those things.
"What the fuck!"
He leaped away in a blur, putting some distance between himself and the other man. Orochimaru, arguably the most infamous missing-nin in the world and another of the three Legendary Sannin, simply smiled back.
"You," Jiraiya growled, "Why are you here and – wait, do what with the what?"
"Save the world," Orochimaru repeated patiently, "I know you were the dead last of our team, Jiraiya, but I surely shouldn't need to explain things that I told you literally five seconds ago at this point."
"Explain why I shouldn't punch you in the face right now."
"Because of time-travel."
"What?" Jiraiya got the feeling he would be saying that a lot in this conversation.
"Indeed," Orochimaru folded his arms, "For you see, through the power of science, I, the greatest researcher this world has ever known, have mastered time like no other before me! I have successfully projected my consciousness back decades into the past!" he laughed maniacally for a moment.
Jiraiya blinked. "And… what, did you come back to warn us of an impending catastrophe that ended the world? That doesn't sound like you."
"Oh, no," Orochimaru shook his head, "I mean, there is an impending catastrophe, but our apprentices solve that neatly enough. I just did it to see if I could."
Jiraiya nodded. That sounded more like Orochimaru. Then an important part of Orochimaru's statement stuck in his mind. "Wait, I have another apprentice? You have an apprentice? They work together?"
"'They may have blown each other's arms off in a deadly battle for the fate of the world at one point," Orochimaru admitted, "And my apprentice may have tried to kill yours… a few times? Yes, we'll go with a few. But for the most part, yes, they are friends and comrades."
"A few ti – okay, no," Jiraiya shook his head, realising he was being taken in by this madness, "You do realise this all sounds like absolute nonsense."
"If you think it sounds bad, you should have tried being there," Orochimaru agreed, "Which you weren't, by the way. Remember those three strays you took in over in Rain country? The ones I suggested we kill? The one with the Rinnegan went insane and started believing he was a god, is now the public leader of Akatsuki and not only killed you but also single-handedly levelled Konoha. Now, I'm not going to say 'I told you so', but..." he shrugged.
"Nagato?" Jiraiya was taken aback, "Wait, public leader?"
"Yes," Orochimaru continued, "The real leader pulling his strings is Uchiha Obito."
"Minato's dead student?"
"He's pretending to be Uchiha Madara," Orochimaru confirmed, "Mind you, his strings are being pulled by the real Uchiha Madara."
"The dead one?"
"Being dead seems to lose a lot of its meaning in the future," the Snake Sannin nodded, "Given how much of my life's work was spent trying to gain immortality it actually got a bit irritating. Of course, his strings are actually being pulled by the mother of the Sage of the Six Paths, who happens to be both the originator of chakra and an alien."
"You're just fucking with me now."
"I wish I was," his fellow Sannin commiserated, "But enough about that. Want to know how to save the world?"
"My head says no, but my burning curiosity says yes."
"Good," Orochimaru grinned, "So, you know your student's son?"
"Naruto?" Jiraiya asked guardedly.
"Yes, Naruto. He's going to save the world when he's older. So you should probably get on that right away."
"Naruto is my apprentice? Naruto saves the world?"
"Yes, it turns out you were genuinely right to believe that 'Child of Prophecy' nonsense," Orochimaru admitted, "I guess I actually owe you that beer."
"Heh, never doubt the J-man," Jiraiya grinned, before remembering something the other Sannin had said earlier. "Wait, so your apprentice tries to kill Naruto?"
"Of course. Fortunately, the future Seventh Hokage is a very forgiving person," Orochimaru nodded again, "He even invited me to his wedding. I couldn't attend, but I sent a congratulations. You didn't send a congratulations, though. For shame."
"What – but – you just said I was dead! That totally doesn't count!" Jiraiya gaped.
"Bah," his rival laughed smugly, "I'd died at least twice by that point and it didn't stop me. Excuses, excuses. On that note," he added offhandedly, "I'd dearly like to actually attend this time, it sounded like a wonderful event, so if you do anything to interfere with his future relationship with Hinata Hyuuga I'm going to commit terrible acts of science on your corpse."
"He gets married to a Hyuuga girl?" Jiraiya paused, ignoring the threat entirely – he and Orochimaru had been trading banter like that for decades, after all - before asking the most important question, "Is she a looker?"
"Regarded as one of the most beautiful women in Konoha in the future, I believe," Orochimaru shrugged, "Though I'm not really the correct person to judge, romance always escaped me as you well know."
"Oh yeah," Jiraiya gave his future godson an imaginary thumbs up, "I can see I taught… er, teach, future Naruto well!"
"Yes, let's go with that," Orochimaru agreed, "Anyway, I've got things to do, people to see, other people to annoy immensely, possibly even some people to kill, you know how it is, so here, have this scroll full of extremely important information and toodles!"
"Wait -" Before Jiraiya could try to stop him or take him in, his former team-mate dissolved into a pile of snakes, which then split apart and slithered off into the trees, leaving a stupefied toad sage holding an unassuming-looking scroll.
"Well," he said aloud, "I'm now mostly convinced that someone's spiked my drink, so fuck it, let's see what you're all about," he eyed the scroll, inspecting it carefully for traps.
After half an hour of thorough checking, he carefully opened the scroll. Inside was… a dossier? A series of dossiers, in fact. He began reading the first one, and his eyebrows hit his hairline.