Looking for those fics where romance blossoms between characters from 'Naruto' and 'High School DxD' that don't exist in either canon is a real hunt. It's less about defined pairings and more about which character gets dropped into the DxD universe and who they naturally click with. A lot of authors seem to default Naruto with Rias or Akeno, which honestly feels a bit lazy sometimes—it's just slotting the powerful protagonist with the most prominent female characters.
I got way more interested in a story that paired a post-war, weary Naruto with Kuroka. The dynamic wasn't about raw power, but two people who understood being outcasts and living outside the normal systems. The romance built slowly over the course of the fic, with Naruto's persistence chipping away at her cynical front. It felt earned, not preordained. Another one had Sasuke, post-redemption, developing something with Rossweisse. It was all about two warriors bound by duty and past loss finding a quiet understanding, which was a refreshing change from the usual high-drama stuff.
You also see a lot of cross-universe pairs for side characters. I remember one where Shikamaru ended up with Tsubaki, the sword-wielder from the Sitri peerage. The author played up the strategic minds connecting, which was a smart angle. Finding these takes serious digging through fanfiction.net and AO3, filtering out the harem power fantasies to find the stories that actually bother with character voices. The tags are your best friend, but even then it's a lot of sifting.