One Piece - Grand Battle Swan Colloseum ROM Download can be obtained free for WonderSwan on EmuGames.net only. Play emulator game in English for the USA region. One Piece Grand Battle Swan Colloseum is a WonderSwan ROM that you can download to your computer or play online within your browser. You can also download roms such as LEGO Star Wars III The Clone Wars and Shonen Jump's One Piece that work on all devices including desktop and mobile. Be sure to rate the game if you enjoyed playing this ROM.