Sometimes I think people get too caught up in the whole 'unflappable' side of Katakuri and forget he's essentially the family's emotional cornerstone. That's where a compelling scene starts for me—not with grand declarations, but with someone seeing the weight he carries. Imagine a moment of quiet domesticity after some big event in Tottoland, maybe you're a new crew member or a diplomat. Everyone else has scattered, and you find him alone in a kitchen corridor, leaning against the wall, just staring at nothing. The mochi arm is maybe half-transformed, sticky and imperfect, which he'd never allow publicly. You don't offer pity, just slide down the wall to sit nearby and start talking about something inconsequential, like the weird taste of a new island's fruit. The romance isn't in touching; it's in being the one person he doesn't have to perform for, where his silence isn't intimidating but shared. He might not reply, but later, a perfectly formed mochi dumpling with your favorite filling appears by your door. His love language is observation and unspoken provision, a stark contrast to the chaos of the Charlotte family.
For the actual 'scene,' a conflict that tests his control works well, but internally. Maybe the reader gets seriously injured defending a younger sibling, something that mirrors his own protective drive. His composure cracks—not a full meltdown, but a single, sharp 'Why?' growled out, his gaze burning. The compelling part is the aftermath, how he meticulously tends to the injury with a terrifying focus, hands steady but jaw clenched. The tension is in what he doesn't say, the way his usual distant respect shifts into something fiercely, quietly personal. He's a man who communicates through action and unbreakable will; a reader character needs to be someone who can interpret that and respond in kind, not with flowery words, but with an equal strength that earns his regard.