Marco is an Italian aid worker who was volunteering in the Kenyan Village that Number Three lived and was killed in. He first meets Adam and Ivan as they pose as aid-workers to try and identify Three. He is suggested to be the leader of the camp.

He is summoned, along with a local Doctor, when an elderly villager finds Adam's broken body after he had dragged himself out of the ravine and a quarter of the way through the jungle. Marco offers him a place with his volunteer camp, first as a place to recover and then as a volunteer.

He does not ask Adam any questions about his condition, as anyone else would. Adam assumes that Marco had guessed that Ivan was responsible, since he left Kenya on the day of Adam's disappearance without a word to anyone at camp. Adam thinks that Marco's generosity towards him is due to pity.