The Player is a customizable character in Bakugan: Defenders of the Core. Unlike the Player in Bakugan: Battle Brawlers, this Player does not have any Guardian Bakugan, but he uses the Pyrus Attribute only.
While doing some Bakugan Interspace testing, the Player uses a virtual version of Drago to beat Dan, but soon after, Bakugan Interspace crashed and the Player was sent to an alternative universe where Dan and the others don't even know who the Player is.
The Player helps the Bakugan Battle Brawlers Resistance liberate Earth while working on a method to get back to his universe. On the way, he meets a entity known as "Abyss," who helps guide him in his battles but only reveals herself to him, causing the others to think the Player is going crazy. She does not reveal herself until the final battle between the Player and Spectra, where she is destroyed by the Player's Maxus Dragonoid, and Spectra is defeated.
Afterwards, the Player manages to return to his own universe, and he says that he likes Bakugan.