User blog comment:CoolNiceAtDisney/The “FINAL” Boss Battle/@comment-30084465-20200109184704

Being Maleficent the main villain of the game, it is most likely that the end of the main story will end with a battle against her. And after defeating her, we can unlock her as a playable character.

It would be pretty good, as you say, to see several characters facing her as a team, such as Mickey, Phillip, Rapunzel and other heroes and heroines.