Major differences between Deicide universe and One Piece canon that happen prior to Deicide: Onigashima Aftermath
- Mihawk is Crocodile's first mate in their early days of piracy. Crocodile is Whitebeard's son. Galdino is a cabin boy and later crewmate on their ship.
- Crocodile, Mihawk, Buggy, Doflamingo, Vergo, and Daz have an accidental misadventure together on a lost island in the aftermath of Roger's execution.
- Donquixote Rosinante is the victim of a precursor to the experiments performed on Kuma.
- Caesar Clown is involved in the experiments on the Vinsmoke Siblings, and is the one who assists Sora with her attempt to thwart part of them.
- Marianne/Miss Goldenweek's abilities are due to a devil fruit.
- Vivi is 20 during the events of Alabasta rather than 16.
- Enel is killed during the Skypeia arc.
- Carrot is the crew member who the Straw Hats acquire at Thriller Bark, rather than Brook, and she remains with them throughout.
- Gecko Moria is ejected from the Warlords due to his failure against Straw Hat Luffy. He slinks off from his miserable defeat to get drunk on a resort island, having lost all his drive. He remains there for two years.
- After hearing news of Marineford, Vivi becomes determined to rejoin the Straw Hat crew and runs away from her kingdom. She runs straight into Crocodile, adventures with him and the remnants of Baroque Works during the timeskip, and gets a devil fruit for herself.
- Bon Clay, with the encouragement of his fellow prisoners, sneaks out of Impel Down with the intention to join up with the Straw Hats. He ends up with Crocodile and the former Baroque Works members.
- Koala and Sabo discover that Ace's soul is sharing Sabo's body. They reconnect with Ace's former first mate Deuce.
- Luffy spends more personal alone time with Hancock during the timeskip, training on the outskirts of Amazon Lily rather than another island.
- Vergo survives the events of Punk Hazard, his body found in pieces by Doflamingo and reassembled. He is resting/healing outside the city during the events of Dressrosa, but rushes in at the end when he discovers there's trouble. He's in time to save the Donquixote family from captivity by marines, but is unable to get to Doflamingo who is being kept separately.
- Rebecca, (who is 18, not 16) wanting to determine her own path, and not wanting to be forced into a peaceful life after her experience as a gladiator, flees Dressrosa with the Straw Hat crew.
- The Straw Hats are not separated in Dressrosa, and travel to Zou together.
- Crocodile's ship catches up to the Straw Hats as they're leaving Dressrosa. He has a short reunion with Robin, and delivers Vivi to the Straw Hat crew as promised. He then goes after the marine ship carrying Doflamingo, and successfully frees him from custody.
- Viola has a change of heart and rejoins the Donquixote pirates as Violet.
- Events of One Piece Stampede and Film Gold happen.
- Crocodile forms Cross Guild with Mihawk, Buggy, Doflamingo and Hancock.
- The Straw Hats encounter Lim and Adio– something like the events of "One Piece Odyssey" happen.
- When Sanji is forced to leave the Straw Hats for his wedding Rebecca goes along to watch after him. Luffy and the rest of the Straw Hats go after him immediately, despite Sanji's insistence not to.
- After the events of Whole Cake Island, Caesar Clown joins the Straw Hat crew on a permanent basis. Luffy insists that his position on the crew is "Chopper's assistant".
- During the events of Whole Cake Island, Rebecca gets close to the Vinsmoke siblings, and in the aftermath of the event they adopt/kidnap her. The siblings abandon their father to Big Mom's wrath and sail away, after which they convince Rebecca to undergo enhancements similar to their own.
- In the aftermath of Whole Cake Island, Pudding flees the Charlotte family trying to find her own way in life. Katakuri discovers her leaving, and follows her as a sort of bodyguard. They eventually end up running into the Vinsmoke Siblings and Rebecca.
- Koala, Deuce, and Isuka accompany Sabo (and Ace) on their raid on Mary Geoise during the Revelry.
- Otama is 18 years old, rather than 8.
- On Wano, Luffy finds out about Kaido and King's backstory and is unsettlingly reminded of himself and Zoro. These feelings lead him to resist his urge to kill Kaido during their battle, and to discover that "Gear 5" has some kind of mind of its own.
- Big Mom also survives the battle on Wano, but winds up in a coma. She is brought back to Tottoland by her children.
- Deicide: Onigashima Aftermath starts, and Deicide and One Piece canon completely part ways so much as to become unrecognizable.