The day has been… off . Even while high above the rest of the crew in the Crow's Nest, Zoro hasn't heard the usual yells and laughs, felt the usual shakes and quakes of the Sunny, been annoyed to the point of groaning extra loudly while training. He was able to take his naps without any interruption – outside of that idiotic cook calling for lunch. He was able to train without worrying about anything, and that worries him.
It's after dinner and multiple bottles of sake when he walks over to Sunny's head, his captain sitting there like it's his seat. (It was always his seat, he remembers. He was always sitting right at the head of that dinghy, and then sitting right between Merry's curved horns like it was a throne. When he became the Pirate King – because it was a matter of when , not if – Zoro was sure Sunny's head would be Luffy's choice of a kingly throne.)
It's quiet for a minute or two as he stands there. He doesn't say anything and neither does his captain… which is odd. Usually, Luffy would say something idiotic just for the sake of saying something. It's just in his nature, like a second instinct. But now? Nothing.
"You have nothing to worry about, you know," is what Zoro says. He doesn't really know what to say – words aren't his speciality, swords are – but he remembers the first time they were in a situation like this. He said something like that, and it seemed to work because… well, here they are now. It seems only right to say again.
Luffy is quiet for a little bit longer. "Today's Ace's birthday."
Zoro crosses his arms.
"He would've been 23."
Zoro faintly nods. It's been three years since they were all separated and since the climatic War of the Best. He hates himself because he wasn't there for his captain back then. "Some first mate I am" is the thought that runs through his head. He's sure the others feel the exact same way. It's the reason why they are who they are now: stronger, prepared for anything, willing to lay their lives down for the sake of making this straw hat wearing man the second Pirate King. (He's not the boy he used to stare at in their dinghy, the ocean waves rushing back and forth, back and forth, back and forth. He's a man, possibly more of one than Zoro is himself. He won't admit it out loud, though.)
In the time the crew has been back together, no one has breached the subject of Luffy's brother. The elephant's in the room, and they serve it tea and cookies.
"What if I died instead of him?" Luffy asks.
Zoro stops breathing for a second and looks at Luffy. He's looking out at the wide, dark ocean, so all Zoro sees is the back of his red shirt billowing in the light breeze. This feels familiar. He wished it didn't.
"Didn't you say you wouldn't call me your captain if I couldn't protect the ones I loved?"
"Yes." Luffy is quiet again. He leans down, his head almost in his lap, and his shoulders shake just a little. Zoro stares at his billowing, red back for a little while longer. "But I'll give you one time to fail. That one failure should be enough to fuel you to get stronger and kick those Marines' asses and be the next Pirate King. Show Ace that old geezer Whitebeard would never be King as long as you still own that hat and your name is Monkey D. Luffy."
Luffy's shoulders stop their miniscule shaking and he sits up straight. He sniffs a little and wipes his nose. He turns around with wide brown eyes and a smile as big as the moon guiding the Sunny… and Zoro smirks right back at him.