Grimlock is an Autobot. He is also part of the subgroup, the Dinobots, of whom Grimlock commands. Grimlock is the most feared and the most powerful of the Dinobots. He is a great warrior whom everyone respects, friend or foe. Grimlock has no mercy, just contempt to the ones he considers beneath him, most of them being humans but sometimes it is Optimus Prime. Grimlock would be willing to take Optimus Primes' leadership of the Autobots. Grimlock will take leadership when he is given the opportunity.
One of Grimlocks most known features is his caveman speech, which makes his phrases shorter because he uses "me" instead of "I". When he does the caveman speech, people think that he has low mental capacities or that he is practically dumb because of his way of saying his speech; and by doing the caveman speech, he is making others think that he is less intelligent than he actually is.
Grimlock turns into a Tyrannosaurus Rex in his alternate mode. When he is in Tyrannosaurus Rex form, he can snap almost anything with his jaw from steel to Decepticon arms or legs. Grimlock is considered one of the strongest Transformers. He could possibly be equal or greater to Optimus Prime or Megatron in certain things. When he is in robot mode, he is armed with a powerful energo-sword which can slice a 2 foot thick concrete wall in half. Grimlock also has a double-barreled, self-propelled rocket launcher.