Grimlock is a wild card among the Autobots. Huge and powerful, he is also ego-maniacal, impatient and willful. He views Optimus Prime as a weak leader, too afraid to make the tough calls and act on instinct. As such Grimlock is more than ready to disobey orders if he thinks the ends will justify the means. His one obvious redeeming feature is his attachment to his team. As leader of the Lightning Strike Coalition Force, he has gathered together a group of similar minded individuals he would do anything for. Together they handle the jobs the Autobots don't have the stomach for.

Shockwave's experiments not only granted Grimlock a new alternate form, but increased his power tenfold. Unfortunately this was at the cost of his intelligence. While far from stupid, Shockwave's experiments have made it more difficult for the former field commander to think rationally and made his already prominent rage issues all the more severe. Fortunately his team, reborn as the Dinobots, have become more tight-knit than ever. Together they are helping overcome his disgust at what Shockwave has done to him and see the advantages of his new power.