Major is also their younger brother.
In Rat-A-Tat Father's Day special,Major's father died in a plane explosion,so he sent his son Major to live with Colonel and Don,he used to walk on 4 legs but now he walks on two legs.
His full name is Major Saab
Like the other main characters, Major dies and is revieved repeatedly in many episodes. He was first shown as a craving dog who can't get enough food. Later on, Major learned to use a military gun.