Wikipedia: [Macrinus ] was Roman Emperor from April 217 to 8 June 218. He reigned jointly with his young son Diadumenianus. Macrinus was by origin a Berber from Mauretania Caesariensis. A member of the equestrian class, he became the first emperor who did not hail from the senatorial class and was the first emperor from Mauretania. Before becoming emperor, Macrinus served under Emperor Caracalla as a praetorian prefect and dealt with Rome's civil affairs. He later conspired against Caracalla and had him murdered in a bid to protect his own life, succeeding him as emperor.

He was executed in Capadoccia, after Heliogabalus took over as emperor. After Macrinus' death, the Senate declared him and his son enemies of Rome and had their names struck from the records and their images destroyed. So an image of him must be rare.