Warning: SPOILERS for One Piece Film: REDThe appearance of Luffy's Gear Fifth in One Piece Film: RED raises a lot of questions among the fans on how the movie fits the overall timeline of the series. The presence of the Straw Hat captain's most powerful form means that the movie should take place after the Wano Country Arc, but there are other elements that contradict this.
One Piece Film: RED has a difficult job in remaining coherent with the main series' continuity after the manga concluded what is possibly its most important story arc ever, with the anime trailing only slightly behind. In the final battle against Kaido in Wano, Luffy awakened the powers of his Devil Fruit and acquired a new form, Gear Fifth. He uses that transformation briefly in One Piece Film: RED too, but there are a few conflicting elements that make it difficult to establish if the movie actually takes place after Wano.
One Piece Red Writer Reveals it Was Originally About A Different Hero
One Piece Film: RED was originally conceived as a prison break story where Luffy would go rescue a beloved character in the series: Mr. 2 Bon Kurei.Luffy's Gear Fifth in One Piece Film: RED Breaks the Timeline
Judging from the status of the Straw Hat Pirates, One Piece Film: RED should indeed take place after they left Wano. Jinbe is part of the crew, and he joined permanently only in the land of the samurai. Zoro uses Enma, a powerful sword that he acquired in Wano and formerly belonged to its ruler, Oden. More importantly, Luffy is recognized as a Yonko, a title he received only after beating Kaido during the climax of the battle for Wano, and in the movie Luffy also uses his most powerful form in One Piece form, Gear Fifth, which he acquired during that gruesome fight. However, there is also one big contradiction that does not allow putting One Piece Film: RED in the post-Wano timeline.
Big Mom's Inclusion in One Piece Film: RED Makes No Sense
The movie, in fact, also features the Big Mom Pirates in a minor role. This should not be an issue, because they all survived the Whole Cake Island Arc, when the Straw Hats went to rescue Sanji from his arranged marriage. However, Big Mom also appears in One Piece Film: RED, which should not be possible, as she was defeated and, apparently, killed by Trafalgar Law and Eustass Kid during an epic battle in Wano, at the same time as Luffy's clash with Kaido. This is not easy to explain, and it could even be a tease that Big Mom survived her fall into the lava pit (as she promised she would do) and will return later in the series, but for the moment it just makes One Piece Film: RED's timeline more confusing.
Uta's Canon Status Makes One Piece Film: RED Even More Confusing
The solution to all of this confusion is, that One Piece Film: RED is non-canon as most of the movies are. While most long-time fans will be well aware of this when watching RED, it's not immediately clear to a more casual viewer. To make matters worse is RED's chief antagonist, Uta. Uta is canon to the One Piece manga, even if the events of RED aren't. Given Uta's importance to the backstories of Luffy and Shanks, it's disappointing that RED was made non-canon. Despite the timeline problems caused by Uta, Big Mom, and Gear Fifth though, their inclusion in RED isn't inherently a bad thing.
Luffy using his Gear Fifth in the movie is mostly a treat to fans because it makes for an incredibly epic sequence when Luffy and Shanks unleash their most powerful techniques at the same time. While brief, this moment still anticipates the debut of Gear Fifth in the anime, and it was definitively worth having it in the movie. If it were not for Big Mom's appearance, the hugely successful One Piece Film: RED could have easily taken place right after the Straw Hats left Wano and Luffy awakened the power of his Gear Fifth.
One Piece FIlm: RED is available now on Crunchyroll!