One Piece: Nico Robin

Nico Robin is the archaeologist of the Straw Hat Pirates. She was originally introduced as the vice president of Baroque Works, known as Miss All Sunday, before joining the Straw Hats. She is the seventh member of the crew, the sixth to join, and, like Nami and Usopp, is the second to rejoin, doing so near the end of the Enies Lobby Arc.

One Piece: Nami (Fishman Island)

Fishman Island marks the beginning of 20-year-old Nami. Most people on the Internet don't like Nami's redesign because they say it makes her look generic. While I agree the old version of her was superior, I think older Nami has merit as well. Not to mention her outfit permanently includes sandals.

Part 1: http://animefeet.blogspot.com/2014/05/one-piece-nami-arlong-park-arc.html
Part 2: http://animefeet.blogspot.com/2014/10/one-piece-nami-grand-line-arc.html
Part 3: http://animefeet.blogspot.com/2015/03/one-piece-nami-little-gardendrum-island.html
Part 4: http://animefeet.blogspot.com/2015/04/one-piece-nami-alabasta.html
Part 5: http://animefeet.blogspot.com/2015/08/one-piece-nami-jayaskypiea.html
Part 6: http://animefeet.blogspot.com/2013/08/one-piece-nami-davy-back-fight.html
Part 7: http://animefeet.blogspot.com/2015/08/one-piece-nami-water-7enies-lobby.html
Part 8: http://animefeet.blogspot.com/2015/08/one-piece-nami-thriller-bark.html
Part 9: http://animefeet.blogspot.com/2015/08/one-piece-nami-spa-island.html
Part 10: http://animefeet.blogspot.com/2015/08/one-piece-nami-sabaody-archipelago.html
Part 11: http://animefeet.blogspot.com/2015/08/one-piece-nami-weatheria.html