Naruto x SMT fanfic, but it's him and the protags of SMT 1 and 2 (alongside their friends) in SMT If...
Naruto (the protagonist of... Naruto): So you're the reincarnation of Adam? From the bible?
Kazuya (the protagonist of SMT 1): Apparently.
Naruto: And that brown-haired guy that looks like Neji's is the reincarnation of Abel? Also from the bible?
Kazuya: Don't know who Neji is, but yeah, it's implied. Sorta, he might just be Jes—
Naruto: And the other dude that looks like Sasuke with a flat top, glasses and self-esteem issues is the reincarnation of Cain?
Kazuya: Also don't know who Sasuke is, but apparently yes, It's implied. Or he might just be the Anti—
Naruto: And the girl that Neji-looking guy is flirting with Eve? His mom? Your wife?
Kazuya: Yes, but no?
Naruto: Elaborate.
Kazuya: So that's not Aoi—the reincarnation of Eve—that's just a girl that looks like a younger Aoi and is also named Aoi.
Naruto: But she still looks like the real Aoi.
Kazuya: Kinda? Give or take 2 years, and the bangs. She's going with the hime-style haircut.
Naruto: Gotcha, but that's still, kinda his mom, right? Like, you just said that she's like her but younger.
Kazuya: I meant that appearance-wise, not personality-wise.
Naruto: But it's still her? Like, this is still incest, right?
Kazuya: Kinda? I don't know man.
Aleph (protag of SMT 2): Hey guys, what're you guys talking about?
Naruto: The incestual implications of dating someone that looks like a younger version of your mom.
Aleph: Ahh, got it. Heh "chuckles ", been there.
Naruto: ...
Kazuya: ...
Aleph: ... What?
Naruto: What do you mean "what"!?
Kazuya: You can't just say shit like that and not explain!
Aleph: What's there to explain? My mom didn't know who I was and we almost banged, until we both found out that I was her child.
Naruto: Dude, what?
Kazuya: The fuck do you mean "we almost banged", how the fuck couldn't she tell apart her own child?
Aleph: That's because we're almost the same age!
Naruto: Dude. What. The. Fuck!?
Kazuya: What do you by that. What do you mean by that? What do you fucking mean by that, Aleph!?
Aleph: When I was born the place I was in accelerated my growth by some years, so I could be a gladiator and stuff!
Naruto: WHAT!?
Kazuya: Oh my god...
Aleph: Yeah, it was messed up. Like, I was technically a baby.
Naruto: Damn, man. I'm sorry.
Kazuya: Yeah, same.
Aleph: It's fine, it's fine. I mean, out of context, I would probably freak out too.
Naruto: Yeaaaaaah...
Kazuya: Hmmmmm...
Aleph: ... "sighs", what now?
Naruto: So...
Kazuya: Yeah, uhhh...
Aleph: What? Spit it out.
Naruto & Kazuya: How old are you?
Aleph: 2 years old.
Kazuya: What.
Aleph: I'm 2 years old.
Naruto: I beg your finest fucking pardon?
And so shenanigans ensue, until a nerd gets bullied and demons start appearing at school. As such is life. Probably.