Marcus is a close friend of protagonist Lucius Modestus and a professional marble sculptor. He collaborates directly with Lucius, carving stone to execute architectural designs for bath-related construction projects, including commissions for prominent figures like Consul Lepidus and Emperor Hadrianus. Residing with an elderly master, Marcus provides regular care that impacts his schedule. This responsibility leads Lucius to develop an indoor bath solution to accommodate Marcus’s time constraints, enabling Marcus to fulfill his obligations to the Emperor punctually. Sociable and pleasure-seeking, Marcus frequents public baths with Lucius, enjoying lively atmospheres and services such as hair removal—contrasting with Lucius’s initial discomfort. Their friendship centers on regular socialization in bathhouses, where they converse and drink. During Emperor Hadrianus’s Jerusalem military campaign, Marcus participates in constructing therapeutic baths for soldiers, demonstrating his continued professional support for Lucius in significant projects. Marcus is an adult male with gray hair cut to ear length.