Honestly? I'm always surprised by how much depth some writers manage to pull from Dabi's and Hawks' dynamic. It's a tricky pairing because on-screen, a lot of their emotional connection is subtext and shared history you have to piece together. Fanfic writers really latch onto that gap. I've read ones where Hawks' internal monologue is just this frantic, guilt-ridden spiral about his mission and the person Dabi is versus the boy he might have been, Touya. They'll dig into the sensory details—the smell of burning feathers, the cold press of staples against skin—to ground the emotional chaos.
A common thread I see is framing their emotions through the lens of performance and authenticity. Hawks is performing for the Commission, Dabi is performing for the League, so when they're alone in these stories, the breakdown of that act is where the real feelings bleed through. It's less about grand declarations and more about Dabi letting his guard drop enough for his voice to lose that theatrical rasp, or Hawks forgetting to smirk. That moment of quiet recognition, where they see the other's exhaustion, hits harder than any fight scene.
Some fics really lean into the tragic irony too, how their assigned roles as spy and villain make genuine understanding both possible and utterly doomed. The emotion comes from the inevitability, I guess. You're reading it knowing how it ends in canon, so every tender moment is already stained with ash.