User blog comment:Neowitch/Paranoid Similarities/@comment-1595565-20120131143507

Both second to last males recruited in each ocean were acting like they were reluctant to join when in fact they really wanted nothing more. They both joined right after the crew received a ship and they both specialize in attacks that involve shooting things. They also both were and are responsible (in some way) of looking after their ships. Also, both have some kind of eyewear and people they looked after back home. Starting with Luffy, each odd numbered member has an ability that is completely exclusive to them and their skillsets alone. Luffy has his Devil Fruit, Nami has her Clima-Tact, Sanji has his Kuroashi, and Robin and Brook also have Devil Fruits.