No he is the secondary main character. The main character is Luffy, and he is second to no one.
And suprise here....but there are two main antagonists this arc. One for Luffy which is the Yonk that he said he will take down. And one for Zoro which is the Shogun he said he will take down. Luffy shows no interest in Orochi, Zoro shows no interest in Kaido. Please all of you stop having bad reading comprehension.