Weirdly, I've always felt the tension in those stories hinges less on open conflict and more on what they represent to each other. Crocodile is this monument to control—cool, calculated, his plans hidden beneath layers of sand. Doflamingo is the opposite: chaos draped in garish colors and loud proclamations. The real friction isn't just who's stronger; it's whose worldview gets validated. A lot of fics I've read nail this by having them constantly trying to dismantle the other's systems, like Doffy trying to make Croc lose his composure just to prove his order is fragile, or Crocodile quietly undermining Doflamingo's theatrical power plays by pointing out the logistical flaws. That silent war of philosophies is way more engaging than a straight-up brawl.
I saw one crossover AU that really dug into this, where Crocodile ran a legitimate shipping conglomerate and Doflamingo was a media mogul. The tension was entirely corporate espionage and social maneuvering—poaching executives, sabotaging press releases, that sort of thing. It kept the core of their characters but translated the rivalry into a modern setting where the 'strength' was influence and market share. The author had this great line about how Crocodile's office was all clean lines and muted tones, a direct rebuke to Doflamingo's neon-lit, chaotic studio. The tension was in the environment as much as the dialogue.
Most of the time, though, the stories that linger with me are the ones where the rivalry masks something else, a grudging recognition that they're two sides of the same coin. They're both former Celestial Dragons who chose different paths of rebellion, both schemers who built criminal empires from nothing. That shared history—even if they never acknowledge it directly—adds a layer of complexity. The tension isn't just animosity; it's the discomfort of seeing your own potential failures and twisted ambitions reflected in someone else. You end up wondering if they hate each other so much because they understand each other too well.