"Among the winners, there is no room for the weak!"
The most fearsome and powerful of the Dinobots, Grimlock would gladly usurp Optimus Prime's role as Autobot Commander if he thought he could get away with it. For now, he's happy to tear into the enemy Decepticons whenever he can and wait for a more opportune moment to try for the leadership.
Grimlock can be cold and merciless, and shows contempt for those he views as weak, such as humans and even some fellow Autobots. But he is a valiant warrior and his actions command respect from all who are witness to them, both friend and foe.
...............................................................................................................