"Dragon Ball Z: Extreme Butoden" and "One Piece: Great Pirate Colosseum" are both 3DS games that are now available for cross-play. Players can now use various characters in both games such as Luffy and Goku.  

Live Updates Now Available "Dragon Ball Z" and "One Piece" 3DS Players

Bandai Namco announced last September that "Dragon Ball Z: Extreme Butoden and "One Piece: Great Pirate Colosseum" will have cross-game battle update. That day has come and both 3DS games can now be updated for cross-play. A video clip on how this battle will look like could be seen here. The "Dragon Ball Z" and "One Piece" cross-play patch is playable on both online and offline. It should be noted though that the update could be availed at the Nintendo online store in Japan, according to Nintendoeverything. There is no mentioned yet if this is cross-game update is available elsewhere.

"Dragon Ball Z: Extreme Butoden"

"Dragon Ball Z: Extreme Butoden is fighting adventure game presented in 2D graphics. More than a hundred Dragon Ball playable characters duel each other using multiple combos, specific regular moves and super moves, according to Nintendo.  The 3DS game was developed by Arc Systems and release on October 20, 2015. A short video clip of the game could be seen here.

"One Piece: Great Pirate Collasseum"

"One Piece: Great Pirate Collasseum" shares similarities with "Dragon Ball". It's also a 2D fighting game but this time, it features the playable characters from the manga. The 3D game features a basic battle mode. But there is also a mode that lets players select their favorite "One Piece" characters by finishing the story in the game. Even before 3D game's release, it was reported that provisions were made to make it cross playable with "Dragon Ball Z: Extreme Butoden". "One Piece" is also one of the manga inspired 3DS games coming from Arc Systems and release on September 2016. A short video preview of the game could be seen here.