SMG4 is Mario's guardian and closest ally (rival in the War of the Fat Italians series), the de-facto leader of his gang, and SMG3's former nemesis. Very passionate and protective of his work, he seems to play the sane man who is often annoyed or shocked by Mario's idiocy. Despite this, they are the two that began their group of friends that have grown over the years to include many different characters who have joined the duo in going on many zany adventures, and fighting great enemies.