Marco Diaz is the teenage son of Mr. and Mrs. Diaz, Star Butterfly's boyfriend, and one of the main characters of the IG-88's Adventures Series. Marco is kind and supportive. He has a reputation at his school for being the "safe kid" due to avoiding danger and being cautious, though he insists that he is a "misunderstood bad boy". Although he is not used to the kind of craziness that Star brings to his life, he admits that he would like a little danger in his life and finds fun in fighting monsters with karate. He is voiced by Adam McArthur.