Cogman is an Autobot Headmaster and a supporting protagonist in Transformers: The Last Knight.
He is described in the film as a Headmaster, which is a type of Cybertronian diminutive in size that forms the head of a larger 'bot. As a Headmaster, Cogman is almost as tall as the average human.
As the faithful, enduring manservant of the Burton family, the Headmaster Cogman has safeguarded generations of Witwiccans for seven centuries, protecting and maintaining the family's collection of secret artifacts. As a butler, bodyguard, and chauffeur, he's everything you could ask for—polite, proper, possessing a healthy respect for tradition, and unafraid to throw out a dry quip or two. That said, he's developed more than a few.. eccentricities over his hundreds of years of servitude, including an unfortunate streak of "anger management" issues that frequently causes problems for his latest charge, Sir Edmund Burton. Nevertheless, he views Burton as the coolest Witwiccan he has ever served.
A scene involving Cogman beheading Nitro Zeus and using his body like a transtector was scripted for the movie but ultimately went unfilmed. Their respective toys (Deluxe class Cogman and Voyager class Decepticon Nitro) retain the ability to swap heads however.