In Japan, owners of the Nintendo 3DS fighting games One Piece: Great Pirate Colosseum and Dragon Ball Z: Extreme Butoden can now engage in cross-game battles. They simply have to go to the Nintendo eShop and download an update to enjoy both local and online battles. Only one copy of each game is required. As the trailer below demonstrates, many exciting battles can take place, including Super Saiyan Blue Goku vs Gear 4 Luffy.
Again this is for Japan only since One Piece: Great Pirate Colosseum has not been released outside the county.Dragon Ball Z: Extreme Butoden was released in Japan on June 11, 2015, in Europe on October 16, and the US on October 20, 2016. One Piece: Great Pirate Colosseum was released in Japan on September 21, 2016 for the Nintendo 3DS in Japan only. No word on if North America or Europe will get to join in on the action.