Among the winners, there is no room for the weak.
Leading the Dinobots in frontline battles on Cybertron resulted in heavy damages to Grimlock's body, including the loss of his Dinobot alternate mode. Grimlock resolved to do whatever it took in order to get back on the battlefield and his way eventually led to Earth and the Binaltech Project. In accordance with his spirit a body of immense strength was selected and born was the ultimate BT soldier. Grimlock has chosen to fight through the upcoming battles with this new Autobot form.