Fusion Fighters

Xros Heart is the protagonists' army in Digimon Xros Wars.

Digimon Xros Wars (anime)
The Xros Heart army is made up of Digimon from many Zones, who all share the desire to free the Digital World from the Bagra Army, and restore the peace it once had. The founding member of the army is Shoutmon, Taiki's official partner, who wants to become the Digimon King in order to protect his friends. Several of his friends from the Green Zone, Ballistamon, the Starmons, Dondokomon, and Jijimon, decide to join Shoutmon on his quest.

Later on, in the Island Zone, ChibiKamemon also decides to join Xros Heart after he helps them save his friends from Neptunmon.

After being slain in an attempt to break Xros Heart out of a Bagra Army prison in the Magma Zone, Dorulumon's old comrade BlueMeramon asks Dorulumon to join Taiki on his quest to stop the Bagra Army. Having come to terms with his past, Dorulumon decides to finally join Xros Heart, and Cutemon of course joins with him.

When Xros Heart comes to the Lake Zone, they soon find the distraught PawnChessmons, whose leader Knightmon has been trapped in a frozen lake and is near death. Taiki rescues Knightmon, and even helps the knights' princess, Persiamon, defend her castle from the invading Bagra Army. In thanks, Persiamon, Knightmon, and the other PawnChessmons join Xros Heart as well.

In the Sand Zone, Xros Heart is saved from Blastmon and his army of SkullScorpiomon by the timely intervention of Deputymon. He asks them to help him find the Code Crown, and at one point asks them to fight Pharoahmon, but Taiki realizes that Deputymon and Pharaohmon are testing him, and refuses to continue fighting, earning him the Code Crown. This encourages Deputymon to join Xros Heart as well. Baalmon soon shows up to help Blastmon, who is trying to fight off the Blue Flare and Twilight armies, and attacks Xros Heart. Baalmon and Taiki get trapped in underground ruins by a quake caused by Blastmon, and after being blessed by a strange statue of a goddess, Taiki learns that Baalmon was once part of a sect of warriors for that goddess, and that the sect was destroyed when its members were brainwashed by someone in the Bagra Army. Taiki befriends Baalmon, but once they emerge from the ruins, they find that the rest of Xros Heart has been brainwashed by that same Digimon, who turns out to be Ebemon acting under Lilithmon's orders. Baalmon manages to free the Xros Heart Digimon from Ebemon's control, and together they are even able to destroy him, but Lilithmon fatally wounds Baalmon before he can claim vengeance on her. Pharaohmon appears and reveals that Taiki can use the Code Crown to begin a ritual that can revive Baalmon, but Lilithmon summons her pet Machinedramon and orders him and the army of SkullScorpiomon to attack Xros Heart. The Xros Heart Digimon bravely attempt to fend off Lilithmon's forces, but when Baalmon awakens and sees that Xros Heart is about to die to save him, he forces Taiki to end the ritual and go help his friends. As Taiki rushes off and tries to fight Machinedramon, Baalmon dies; however, just as HiMugendramon (the empowered Machinedramon) is about to claim victory, Baalmon is reincarnated as Beelzemon, and with his help, Xros Heart is able to defeat Lilithmon and destroy HiMugendramon. In gratitude, Beelzemon joins Xros Heart.