If we were to analyze the Whole Cake Island Arc, among the many questions that continue to be the subject of debate is the question of why Monkey D. Luffy chose not to bring along Roronoa Zoro when he decided to rescue Vinsmoke Sanji. On the surface, this would seem to be a very confusing choice, as Zoro is Luffy’s number one ally, and together, the strength of both has often been the key driving force that has caused the Straw Hat Pirates to succeed in their dangerous missions. This comes after the events of the previous arc on Zou, where Luffy and Momonosuke discovered that they had the ability to hear the voice of Zunesha, and therefore, there were also clandestine elements within the world of One Piece.
Nevertheless, the long-standing comic rivalry between Zoro and Sanji is also a source of tension that Luffy must then contend with. Taking into account the actions that Zoro showed at Thriller Bark, especially his reaction of “Nothing happened,” which is a testament to his unswerving loyalty to Luffy, it is apparent that Luffy’s choice is not simply driven by ignorance.
Luffy’s Choice to leave Zoro behind was Strategy, and Trust in Straw Hat’s Balance as they Split between Saving Sanji and Preparing for War in Wano

There are a couple of reasons why Luffy did not bring Zoro with him, and the first one is related to the strategic splitting of the crew. At the end of the Zou arc, the Straw Hats and their allies had formed the Ninja-Pirate-Mink-Samurai Alliance, and their goal was clearly defined: to beat Kaidou and liberate Wano. In order to prepare for this battle, the crew split into two teams. The Wano team, which included Zoro, Usopp, Robin, and Franky, was sent ahead of time to stake a claim in Wano, to scout out the territory, and to prepare for the larger battle that was yet to come. On the other hand, the Whole Cake Island team, which included Luffy, Nami, Chopper, Pedro, Pekoms, Brook, and, technically, Carrot, who was not part of the group to begin with, was assigned to a smaller, but more focused mission: to rescue Sanji from his forced marriage with one of Big Mom’s daughters. Luffy simply could not have brought Zoro along because this would have undermined the position of the Wano team. The specific nature of the rescue mission undertaken by Sanji also impacts upon the absence of Zoro. This rescue mission was never planned on a large scale or in terms of an attack-meet mission. This was a covert operation, one that demanded subtlety and discretion. The presence of a swordsman such as Zoro would have increased the level of alertness for this open battle, besides which Big Mom’s army might have gotten wind of the rescue plan. Moreover, Sanji had asked his friends not to involve themselves in his internal affairs. While Luffy had a change of heart in disobeying this request, in that he made up his mind to act, he did so in a manner that kept the number of his rescue team low. The other equally significant reason is the fragile situation between Zoro and Sanji. Luffy, despite being called dim-witted, understands his mates deeply. He would also understand that having Zoro with him in this adventure will lead to a disastrous encounter between the two characters. One of the most famous moments in the series, the ‘Nothing happened’ episode in Thriller Bark, had already shown Zoro to be completely loyal to Luffy and willing to give up his ambitions in favor of the captain’s happiness. His loyalty, however, comes with certain terms and conditions. Zoro can never support someone who disrespects him or watches as Luffy, his captain, is attacked by someone like Sanji.
Luffy’s Decision to face Sanji was an act of Trust, and Leadership that Revealed How Deeply he Understands the Hearts of his Crewmates

The Whole Cake Island arc is also an important part of the story where Sanji finds himself in a situation where he needs to protect the people he loves, including Zeff and people from Baratie. He had to leave Luffy behind despite all odds. Having Zoro in this situation might have become an extremely deadly situation. Zoro’s reaction to Sanji’s words or attacks might have endangered the entire plan, would have destroyed the spirit of teamwork, and would have ended up in a complete catastrophe. However, Luffy was cognizant of this situation, and his display of prudent decision-making skills when he decided to take on the problem by himself showcases that he was not behaving in a rash manner. He knew that because of his special bond with Sanji, he could successfully execute the plan. Further, this arc itself gives us an insight into the complexities that Luffy faces as a leader. As a leader, he is confronted with issues of instincts, planning, and his own knowledge about his crew. The decision to leave Zoro behind is both strategic and personal. It allowed the group to successfully complete their mission without any need for internal conflicts and at the same time preserved the honor and unity of the group as well. This decision also displays some of the complexities developed in the narrative by Eiichiro Oda. Right from the information about Zou that comes from Zunesha to how Luffy comprehends the voices that come from the direction of no one at all, it is clear that the choices are never straightforward and consequential as far as their implications range from the crew members to their world.





This is an interesting question as well as a point, because tbh whole cake island arc was a bit off as Zoro had no action. But the angle you mentioned here does make sense, definitely a new perspective and it’s interesting to read too! Keep up the amazing work