Nippon Ichi is adding multiplayer battles to Disgaea DS, but as of now the only mode revealed is a one on one wireless fight between two players. Before the altercation begins, players can set level caps and other handicaps to balance the encounter. Unfortunately the wireless battles are limited to local play only since Nippon Ichi is not taking advantage of Nintendo Wi-Fi.
As of now, this news is for Japan only. Hopefully, NIS America squeaks Nintendo Wi-Fi play in for North America. Remember NIS America went back to the drawing board for Disgaea: Afternoon of Darkness and added multiplayer combat.
Also the Japanese box art is on the right and it doesn’t reveal any secret characters like Mao from Disgaea 3 who I suspect will make a cameo.