Arena Mode



Joint Struggle is the name of the new multiplayer mode said to be featured in Kingdom Hearts Birth by Sleep. In this mode, up to three players can take on the role of Terra, Ventus, or Aqua, the Keyblade warriors wearing their armor from the secret ending of Kingdom Hearts II Final Mix, rather than their usual gameplay attire.

The names of who is playing with you appear above their respective character and while fighting their HP is displayed like someone who is in your Party.

Gameplay
Not only is Kingdom Hearts Birth by Sleep the first Kingdom Hearts game on the PSP, but it is also the only one of its kind to feature a multiplayer mode. Through a new world called the Mirage Arena, three players can access and engage in battles for cooperative play. It should be noted that the Mirage Arena is a world exclusive to Joint Struggle, as well as the "Friend Cure" and "Cyclone" commands allowed for use.

Trivia

 * This is the first time that Terra, Aqua, and Ventus have ever been playable in their armor, let alone their normal in-game attire.
 * While in the Kingdom Hearts II Final Mix secret ending, the three Keyblade warriors' armored suits were a combination of browns, grays, and other dull colors. In Joint Struggle, however, Aqua's armor is red, Ven's blue, and Terra's yellow. The reason for the color change is currently unknown.
 * Kingdom Hearts Birth by Sleep is the third game in the Kingdom Hearts series to feature a multiplayer mode. The first was Kingdom Hearts: Chain of Memories, and the next was Kingdom Hearts 358/2 Days.