I see it as the purest, most straightforward form of rival-buddy dynamic you can get from 'My Hero Academia.' The canon foundation is just so solid—Tensei's injury forces Iida to grapple with vengeance versus heroism, while Deku's got this massive legacy he's trying to live up to. In fanfiction, writers take that and dig into the mutual respect born from shared desperation. They're both trying to be worthy of a name, just from different angles.
You see a lot of stories where Iida's strict discipline clashes with Deku's improvisational, self-sacrificing style. That friction isn't just for drama; it's how they learn from each other. Iida learns to bend the rules when necessary, and Deku learns to think strategically, to value his own safety a little more. The friendship feels earned because it's built on acknowledging each other's flaws and working to fix them, not just on shared classes or battles.
Honestly, the rivalry side often gets overshadowed by the friendship in fics, which I think is a missed opportunity. There's so much potential in exploring a healthy, driven competition that doesn't stem from envy but from a shared goal to be the best heroes they can be, pushing each other's limits during training. The best fics I've read nail that balance, where you can feel the genuine care underneath the sparring sessions.