Wow, that's a tricky one because the relationship is inherently non-romantic in canon, so those fics have to do some heavy narrative lifting. They often stretch that intense, foundation-shifting bond Jiraiya and Naruto have into something more. It starts with amplifying all the existing emotional beats—the loneliness Naruto feels, Jiraiya being the first real adult who saw his potential and stuck around. Fics will linger on moments of training that felt intimate, or on the grief after Jiraiya’s death, and reinterpret that ache as something unrecognized.
Sometimes it's an age-gap, forbidden love angle, playing on the power imbalance that's already there in the mentorship. Other times it's a full AU where Jiraiya survives, and they navigate a changed dynamic years later. The best ones, even if the ship isn't for everyone, dig into how profoundly Jiraiya shaped Naruto's identity, and then ask what if that devotion blurred lines. It’s less about the romance itself for me and more about an extreme examination of loyalty and legacy.