Please note I have not been able to get Kingdom hearts 2 yet so I am working off 1.
Sorra Donald and Goofy just arrived on a new world. and are searching for the keyhole, when a group of 5 giant heartless surround them they manage to kill the first 3 then Donald and Goofy are knocked out and the last two are circling a wounded Sorra
Sorra: ok two giant heartless to the one me Iíve faced worse odds.
Then an army of small heartless come out of the shadows and surround Sorra.
Sorra: ok two giant heartless and an army to the one me. Well Iíll at lest take some of them with me Iím sorry Kairi I wasnít able to keep my promise.
Then out of the distance we see a trail of smoke rising up into the air and a large group of cars lead by a red truck as they get nearer. They get faster not stopping for the small heartless, when they near the two giant heartless they transform into the Autobots. Bumblebee grabs Sorra Donald and Goofy and transforms to carry them to safety
Prime: you have terrorized this world enough. We will stop you, Autobots attack
The Autobots defeat the reaming heartless quite easily just as Sorra Donald and Goofy start to come forward the sun is over shadowed as the Deceptercons land only instead of the Deceptercon symbol it is the heartless one
Thus a mass beat down insures ultimately culminating in the combination of the Keyblade and the matrix to defeat Unicron who is part of the new heartless leaders.