Why Did Nami Leave The Crew. Its also why the reason Robin had for leaving also didnt make much sense to me. Yea Zeff is strong but at the end of the day its a Yonko Germa 66 that would come for his head not to mention the crews heads.
Maybe because he didnt trust Caesar. In Chapter 9 Luffy formally asks her to join the crew. During the Arlong Park arc specifically episodes 33 and 34 Nami stabs her left hand to help Usopp fake his death before the fishmen.
When Luffy went after her in water 7 is was to find out why she is leaving.
Carina used Nami as a decoy so she could escape leaving Nami to be nearly killed. She then tricks Luffy by saying shell join if he helps her steal from Buggy. Then Usopp resurfaces pun very much intended and the crew learns that Usopp is not dead. Its also why the reason Robin had for leaving also didnt make much sense to me.