Bandai Namco just show a trailer of Dragon Ball Z: Extreme Butoden and One Piece: Great Pirate Colosseum are getting updates to enable cross-play. Both game are a 2D fighting game developed by Arc System Works and published by Bandai Namco Games. These games features characters from One Piece and Dragon Ball Z with signature moves from the manga and anime. You can use support characters to help you in battle. Two of the most popular manga fighting with against each other.
For game modes I know both of them have story mode, gallery, local, online battles and etc. The graphics in the game hi-res sprites with color shading and 2.5d stages. This is not the only crossover that One Piece annd Dragon Ball Z, Dokkan Battle (image below), a Battle Stadium D.O.N a crossover game featuring Naruto, One Piece and Dragon Ball Z and J Stars Victory Vs.
If you are a fan of One Piece and Dragon Ball Z buy this game and get the cross play update. Dragon Ball Z: Extreme Butoden and One Piece: Great Pirate Colosseum are available on Nintendo 3DS.