Maleficent says she has great plans for Pete. Presumably this is something that could make him stronger.
What if the true Kingdom Hearts were to reveal itself during the battle between the XIII Darnesses and VII Lights? When the battle is over it would still be there and Maleficent could just wait for the heroes to be tired out from their battle then come for Kingdom Hearts with Pete with her. However, Pete could very well turn on Maleficent and either stay back while the heroes take her on or take her out himself. Then Pete would be able to use Kingdom Hearts in an attempt to take out the heroes. There is a good possibility that Pete could become the plot twist final boss of KH3.
Reference
Maleficent says she has great plans for Pete. Presumably this is something that could make him stronger.
What if the true Kingdom Hearts were to reveal itself during the battle between the XIII Darnesses and VII Lights? When the battle is over it would still be there and Maleficent could just wait for the heroes to be tired out from their battle then come for Kingdom Hearts with Pete with her. However, Pete could very well turn on Maleficent and either stay back while the heroes take her on or take her out himself. Then Pete would be able to use Kingdom Hearts in an attempt to take out the heroes. There is a good possibility that Pete could become the plot twist final boss of KH3.