The creator of the long-running ShōnenMangaOne Piece, which is over seven hundred chapters in length and still going strong. Noted for his unusual art style and eccentric and imaginative character designs.Something of a manga prodigy, he won several awards with his manga Wanted! at the age of seventeen. This landed him a job at Shonen Jump despite his young age, but he worked only as an assistant at first; it was five years before he began a series of his own, but even then he started One Piece at the Improbable Age of 22. Despite having been in the industry for half his life, he is still known for having a fanboyish love of manga in general, especially Dragon Ball. His playful approach to his work has won him a lot of fans.He also worked as an assistant on Rurouni Kenshin.
Tropes associated with Oda:
Author Appeal: Crossdressers. In the character design notes for Rurouni Kenshin, Nobuhiro Watsuki says that Kamatari, a crossdressing character, was inspired by one of his assistants suggesting a character based on the pun, an "okama with a kama", or a "crossdresser with a scythe". Although the assistant is not named, because of this trope, everybody guessed that this assistant was Eiichiro Oda. In a later interview, Nobuhiro Watsuki confirmed that this guess was true. Watsuki explains that Oda's original concept for Kamatari was a masculine looking crossdresser with effeminate mannerisms like the crossdressers in One Piece (Mr. 2 anyone?), but Watsuki had trouble drawing such a character and ended up making Kamatari a pretty crossdresser.
Sunglasses are possibly a new appeal of his. Several characters suddenly wear sunglasses in their post-Time Skip design (Robin, Smoker, Pappug), and the same goes for unusually many of the recently introduced characters (though several of the "older" characters also have sunglasses). However, a reason for this may also be that the characters are drawn with sunglasses because it hides their eyes, and if he doesn't have to think of new types of eyes for every new character design, the Cast of Snowflakes tendency is easier to retain (or at least he can trick the readers into thinking it is always retained).
Animals. Though according to himself, it's not as much that he loves animals, he just loves drawing them. That said, Oda is hardly an animal hater with how a noteworthy lot of the named characters in One Piece are animals (mostly minor characters, but also a couple majors and one main character), and random animals are featured on 99 % of all title pages (except for the canon cover stories).
Art Evolution: His art progressively became less cartoony, character designs (especially his women) are now more diverse, and his panel settings are also more detailed.
Cast of Snowflakes: Indisputably a master of this trope, especially as One Piece went into its later years.
He may be starting to slack a bit off on this tendency recently by drawing sunglasses on the characters (check the entry of Author Appeal above), but even if he is, he is still much better than most of his mangaka peers.
On a more humorous note, it's been joked (and outright stated) by the anime staff that the reason the amount of Fanservice spiked upward was because of Oda getting married and being horny for his very attractive wife (a well-known ex-Cosplay Otaku Girl) all the time, to the displeasure of fans who liked the general lack of such things in the manga early on. For a guy who prefers not emphasizing romance that's not an obvious huge joke in his stories, he sure is a massive softie for his family.
Gonk: Of all shapes and sizes. No, not Oda himself.
It Runs on Nonsensoleum: Many of Oda's SBS answers to questions about how things work in the series. And many of the in-universe explanations, for that matter.
The Perfectionist: Well, at least what his interviews give away. He wonít allow his assistants to draw anything that moves since it may result in an art shift. Check. He writes a movie script, and after that starts from scratch since he isnít satisfied with it and delays the whole production because of it. The end result? Strong World. Check. Additionally, there are several breaks around the year when a new chapter won't appear in Jump and the explanation is always "The author doing research".
There's even a shout out to his shout-outs: his love of soccer is spoofed in one of the theatrical shorts, which has a character named "Odacchi" whose head sports a soccer ball pattern and is voiced by Oda himself.