First Person Pronoun Usage

The First Person Pronoun (一人称) usage means on how every character refers to themselves. The existence of such usage comes from the fact the series' original language is Japanese and it possesses an enormous amount of pronouns if compared to other languages, not only for the First Person, but also for the Second and Third Persons. Thus, how characters use the pronouns of the Japanese language displays an additional layer to the complexity of their personalities. As mentioned before, being this an almost exclusive feature of the Japanese language, this is completely lost when translated into other languages.

Ore
Ore (俺), sometimes written in kana (おれ, オレ), is generally a masculine pronoun, used in the series by a majority of male pirates. However, it is not exclusively masculine; a few women in the series (e.g. Big Mom) use this pronoun since it was used by men and women equally in the past and still is in some regions.

Ora
Ora (おら)

Oira
Oira (おいら)

Watashi
Watashi (私), sometimes written in kana (わたし)

Atashi
Atashi (あたし, アタシ)

Asshi
Asshi (あっし)

Atai
Atai (あたい)

Atakushi
Atakushi (あたくし)

Wasshi
Wasshi (わっし)

Vatashi
Vatāshi (ヴァターシ) is a variant of watashi that Oda invented.

Watasu
Watasu (わたす)

Watakushi
Watakushi (わたくし)

Boku
Boku (僕), sometimes written in kana (ぼく, ボク)

Washi
Washi (儂), sometimes written in kana (わし, ワシ)

Wagahai
Wagahai (我輩)

Ware
Ware (我)

Warawa
Warawa (わらわ)

Uchi
Uchi (ウチ)

Wai
Wai (わい)

Sessha
Sessha (拙者), sometimes written in kana (せっしゃ)

Soregashi
Soregashi (それがし)

Oida
Oida (オイダ)

Oidon
Oidon (おいどん)

Achishi
Achishi (あちし)

Wachishi
Wachishi (わちし)

Wachiki
Wachiki (わちき)

Oi
Oi (おい)

Unu
Unu (ウヌ)

Achiki
Achiki (あちき)

Mu
Mū (ムー)

Trivia

 * In the Vivre Card - One Piece Visual Dictionary, this is translated into English as "The First Person".
 * In the anime, Nami uses the pronoun “atashi” instead of “watashi” like in the manga.