I mean, they're kind of a dream pairing for character study writers, aren't they? On one side you've got Ikki, this guy who carries the weight of being "the worst one" but refuses to quit, and on the other Stella, the literal princess who's lived her whole life under expectations and has this fiery pride. Fanfiction that nails their growth usually starts them as rivals who are almost mirrors—both pushing against their assigned labels, but in totally different ways.
What I keep seeing done well is the quiet intimacy of training together. It's not just about powering up; it's those moments after a spar where they're both exhausted on the floor, and the walls come down. Stella can admit she's terrified of failing her kingdom, and Ikki can talk about the hollow feeling of proving everyone right about being F-rank without actually having to say it. The best fics have their trust building in these practical, grounded steps—learning how the other thinks in a fight, then later, learning what keeps the other up at night.
The real emotional payoff comes when they start fighting for each other, not just beside each other. A story I read last week had Stella taking a hit meant for Ikki, and her internal monologue wasn't about chivalry, it was this fierce, simple thought: "Not him. I won't let them break his spirit again." That's the growth—they become each other's unwavering believer, which is something neither really had before.
And honestly, it makes their canon moments of vulnerability hit even harder.