Marcello is a highly intelligent and serious individual who works as a doctor, dedicated to his profession and driven by a thirst for knowledge. His analytical nature and cold demeanor stem from his hands off upbringing, forcing him to learn his fathers trade from a young age. He has done many unethical experiments over his life, helping his father achieve his goals, even if it takes a black market organ or a fresh corpse. Despite this harsh disconnect in their emotional lives, Marcello's primary focus is on his family, particularly his father whom he strives to impress through his work, and his twin brother, who is his closest friend.

Marcello's serious demeanor and workaholic tendencies make it challenging for him to loosen up and enjoy life outside of work, often leaving him isolated in his dedication to his work, but it's impossible to ignore his brilliant mind, even if it isn't always used for good.