Marco is the de facto leader of the X-Laws, although he can be overruled by Iron Maiden Jeanne. Originating from Sicily, Italy, Marco was orphaned at a young age and raised in an orphanage run by a priest. Along with Jeanne and Lyserg Diethel, he is part of Team "X-I." Marco is extremely loyal to Jeanne and will do whatever it takes to achieve her vision of a world free from corruption and evil. Like many X-Laws members, he sees things in black and white terms: something is either good or bad. Those who join the X-Laws are considered good, while those who don't are automatically labeled as evil.
Marco initially appeared to be gentle, but later it was revealed that he lacks flexibility, which makes him easily annoyed and angry about even small things. This can cause his hair to spike out comically and make him crush his glasses when agitated or stressed. The only thing that seems to calm Marco down is Jeanne or quality chocolate with coffee.
Marco strongly believes in discipline and will punish Lyserg if he stays up late. During fights, Marco tends to give people death sentences. He also has a passion for cars and runs his own dealership.