Digimon Adventure tri. Part 4: Loss

In a society devastated by the effects of an all-out war between heroes and villains, a mysterious giant fortress suddenly appears, engulfing towns and people one after another. Then, a man reminiscent of All Might, the 'symbol of peace', stands in front of Izuku and his friends...

The special takes place during the two year before the Straw Hats reunite on Sabody. Luffy is currently in Rusukaina training to get stronger to take on the New World. However the training is interrupted when Hancock's sisters, Marigold and Sandersonia, are kidnapped by the Byrnndi World, a pirate who was locked away on Level 6 of Impel Down but escaped during Luffy's invasion to save Ace, in order to lure Hancock to him and use her as a hostage against the World Government due to her Shichibukai status. Thus Luffy and Hancock head off to confront him and save Hancock's sisters.

Dr. Raichi is one of the only survivors of the Tuffles, a race that once lived on Planet Plant before the coming of the Saiyans. The Saiyans not only massacred the entire Tuffle race, but also stole their technology and conquered the planet, renaming it Planet Vegeta in honor of their king. Raichi managed to escape with a capsule and found refuge on the Dark Planet, a world at the end of the universe. His only wish is to eradicate the last remaining Saiyans.

After battling their way through all seven Singularities, the Chaldea Security Organization has finally arrived at the endpoint of the Grand Order: The Final Singularity, Grand Temple of Time: Solomon. Now is the time to defeat the root of all evil, Solomon, the King of Mages. Now is the time to reclaim the future. With the final operation looming large, Romani Archaman considers the choices he will soon have to make, Mash Kyrielight dwells on life's limitations, and Fujimaru prepares to receive a new Mystic Code. All their many encounters have led to this moment as Fujimaru and Mash at last embark on their final operation...