Bandai Namco detailed the online multiplayer modes included in One Piece: Pirate Warriors 4, and how it includes coop and multiplayer pvp battles. All of this was revealed by Bandai Namco in an upcoming magazine and was revealed via the usual magazine leaks. Seeing the timing, this should be from this month's issue of V-Jump magazine.

One Piece: Pirate Warriors 4 has four different modes you can play online with your friends. The first one is "Giant Boss Battle" mode, where four players need to cooperate and defeat a giant enemy. Giant characters like Kaido will be used as the bosses you'll need to defeat. The second online mode is "Joint Bounty Battles", where four allied players need to survive and keep fighting to raise their own bounty. The third mode is "Timed Defense Battle", where four allied players need to defend a territory during a time limit. The last mode is "Territory Battle", where three teams of four players fight each other in a territory battle. The team with the biggest territory wins.

Note that this is simply how I personally decided to translate the multiplayer modes' names of One Piece: Pirate Warriors 4. The official English names will end up being slightly different.

One Piece: Pirate Warriors 4 was announced with a first trailer in July 2019 by Bandai Namco, and is the first One Piece Musou game since 2015. Multiple trailers have been released, showing some of the new playable characters, and introducing the various modes of the game.

One Piece: Pirate Warriors 4 launches on March 27 on PC, PlayStation 4, Nintendo Switch and Xbox One.