Hi! I found Zoro's reaction to Sanji leaving strange, and this is my take on the reasons for it. I'm not totally satisfied with this, but I hope you enjoy it! It's my first OP fanfic, so feedback is appreciated!

The crew reunited in a cave on the edge of Wano in a pile of hugs, shouts, tears, and snot, which was really inevitable considering they had just taken down their first yonkou. Or maybe it was inevitable because of the people involved. Sanji felt moved at the possibility that even some of those tears - Usopp's and Franky's, really, because Zoro and Robin weren't they type - were due to his return. Feeling humbled and a little overwhelmed, he hung back and scanned the room. This - this chaos, and happiness, and acceptance, and love - was what he had given up, and he knew he didn't have it in him to walk away a second time, no matter what - or who - was at stake.

Zoro hadn't moved from his seat against the wall since they walked in, but he was watching Luffy carefully with his one good eye. Sanji was surprised to see Eustass "Captain" Kid sitting in the corner, heavily bandaged. Had they gained a new ally? Not that the Supernova seemed to be in the shape to do much at all. He was, however, the only one apparently surprised by the display. Sanji hid his smile behind his hand as he lit a cigarette. Luffy was an education for anyone, as he had recently been reminded. Luffy's bounty had skyrocketed to a billion berries after the fight, inevitably delighting the rubber captain. As soon as Chopper had allowed him to leave the infirmary, Luffy had spent the entire trip to Wano celebrating. At least some good had come out of all the bad.

"You should have seen it, Zoro!" Luffy said, smiling widely and immediately gravitating towards the moss head. "There was an island where everything was made out meat! Even people's clothes!" Sanji saw Law's lip curl in disgust while Zoro remained completely unphased. Law, with the perfect conviction that came with knowing he was the only sane person in the room, opened his mouth.

"That's revolting, Straw Hat."

"Torao!" Luffy greeted, far too cheerfully for someone wearing that many bandages. Sanji felt a twinge at the pain his captain had suffered protecting his family.

"I'm glad to see that your mission was successful," Law commented. Luffy laughed, then focused on the bandages Robin was wearing. Sanji felt himself freeze at seeing another woman he treasured injured. If the crew had stayed together, would Robin have still been hurt? Was this his fault, as well?

"Problem?" Luffy asked softly, glancing at Zoro who was wearing a collection of bandages nearly as impressive as Luffy's. When Zoro simply met his captain's eyes and nodded, Luffy's voice softened further. "You dealt with it?" Another nod and the threatening atmosphere that had begun to surround Luffy dissipated, as if it had never been there in the first place. "Oh, yeah! Brook and Pedro got the poneglyphs for you, Robin," he added, while everyone else in the room froze.

"What?!" Everyone - excluding Zoro and Robin - shouted. Sanji wanted to laugh at their incredulous reactions. What else did they expect from the future Pirate King's crew?

"Thank you," Robin replied with a demur smile, which under normal circumstances would have made Sanji swoon. Brook came over, opened his skull, and the handed large sheets of paper to Robin. There were a lot of people staring at him.

"Does this mean I get to see your-" Brook began before Nami kicked him in the head. Seeing the crew together, interacting normally, Sanji felt his shoulders loosen for the first time in what felt like forever.

"I bet there was a sake island, Zoro, they really had everything!" The idiot swordsman's eye sharpened at the possibility.

"We'll have to go back sometime," he drawled, and his captain nodded enthusiastically.

"Absolutely! And Zoro-"

"I've missed you, Robin. It was such as disaster," Nami complained, sidling up to her friend and leaning her head against the archeologist's shoulder. Despite their injuries, the women looked beautiful standing together. "Luffy almost starved us all to death, then ate poisoned fish and almost died, after that he-"

"Oi! Nami! What are you saying? We kicked Big Mom's ass, ate lots of food, got Sanji back, and stole the poneglyphs! My bounty even went up! It was amazing!" Robin giggled behind her hand. Sanji thought as a summary there was a lot missing, but he supposed it covered the highlights.

"Oi! Zoro! Don't you dare move until I've checked the bandages!" Chopper scolded, coming up beside the swordsman, drawing Sanji's attention away from the women. Not because he was worried about the moss head, of course.

"Law put them on," Zoro told Chopper, apparently hoping that would allow him to avoid a checkup. Chopper's opinion of Law had undergone substantial transformation after seeing what he did for the poisoned kids at Punk Hazzard.

"Zoro's an idiot," Chopper told Law, ignoring his friend's protest, which made Sanji smile a little as he took a drag on his cigarette, "so you've probably had to re-bandage him a pile of times," here Law snorted, "but thanks for looking after my friends!"

"No problem. It doesn't help me if my allies are injured," Law dismissed, because accepting thanks was for other people, apparently. Franky and Usopp came over and were enthusiastically listening to Nami's story.

"Luffy!" Jinbei called out, walking into the cave, "you're needed over here."

"Eh?" The rubber boy asked, getting to his feet and wandering over.

"Yo! Jinbei! Welcome to the crew!" Franky called out happily. "It's SUPER to have you with us!"

"You know what you're in for, right?" Usopp asked seriously. "We have the most unreasonable captain ever." Jinbei just laughed happily, looking almost bashful.

"It will be nice sailing with you, Jinbei," Robin added. "Especially since we won't need to worry about Luffy drowning any more." Sanji understood, because while there were four Devil Fruit users on the ship, and five non Devil Fruit users, there was only one Luffy. Jinbei smiled brightly.

"Leave it to me!"

"Welcome," Zoro greeted, and the word carried weight.

"What was it you needed me for?" Luffy asked, tilting his head to look at his newest crew member.

"Ah! Over here," he said, leading the boy captain away. Nami shook her head an continued with her story.

"You fought the captain?" Zoro asked softly, meeting Sanji's eyes for the first time and interrupting Nami's recounting of their adventures. Everyone went quiet at his tone and Sanji forced himself to hold his rival's eyes.

"Yeah." Zoro stared at him for a long moment before getting to his feet.

"The captain's chosen to forgive you," he said, perfectly serious, the unspoken words telling the cook who hadn't forgiven him, "but, Sanji, if you ever pull a stunt like this again, it won't be the captain coming after you. It'll be me." Sanji nodded, because there was nothing he could say to that. Even knowing Luffy, the fact that he had been allowed to return, despite abandoning his crew, despite raising his hand to his captain, was both a burden of guilt and a gift of love he knew he would carry for the rest of his days.

"What does he mean?" Momo asked after Zoro had left the room. Sanji looked at the boy for a long minute before answering.

"We can afford to have the most forgiving, laid-back, idiot of a captain on the seas," Sanji told him, "because his first mate is none of those things." Momo turned to look at the cave opening Luffy and Zoro had left through.

"Would he really hurt you?" Kin'emon questioned.

"If I harm the captain?" Sanji doesn't even need to pause to consider the answer; it's one of those truths that everyone on the crew knows, but doesn't acknowledge. The swordsman' loyalty is to the captain. Period. "Yeah. If I hurt the captain again, he'll come after me."