Board Thread:Theories and Speculation/@comment-25319479-20180502154141/@comment-3523655-20180503175938

KK = being Jiraiya is what it all seems to point to, which is why it can't be the case, too obvious (after what they did with Tobito, they wouldn't do it again).

I think KK is (in order of likelihood) - Orochimaru's clone of Jiraiya gone rogue. - Jiraiya's bastard son. - Another student of Jiraiya (Minato's comrade), but then he's too young.