Fire Convoy

Fire Convoy (Optimus Prime) is a stern and serious commander, devoted to protecting freedom and innocent life. He has seen the galactic path of conquest and destruction already burned by Gigatron (Megatron) and swears it will not include Earth. Fire Convoy often finds himself in the role of "straight man" to the more comic stylings of the other Cybertrons (Autobots) and Destrongers (Predacons), and tends to treat their humorous exaggerations or personality quirks as statements of straightforward fact. His subordinates view him as a great leader, if stubborn and much too prone to long speeches. Convoy's greatest weakness is his sense of nobility. If an adversary claims to have had a change of heart and discovered inner goodness, he will fall for it every single time. But once he finds out he's been had, they'd better watch out!

(Source: Transformers Wikia, edited)