Milton Haas was a soldier in the United States Army in Europe during World War Two. He served in the army alongside Abraham Simpson, C. Montgomery Burns, Iggy Wiggum, Arnie Gumble, Etch Westgrin, Griff McDonald and Sheldon Skinner.
He took part in a tontine (In fact, he is also the one who accurately defined what a Tontine is), where the last surviving member of the Flying Hellfish would take sole possession of paintings they had 'liberated'. Milton is the first of the Flying Hellfish members to die, of a hernia he got whilst taking the crate with the paintings out of the castle.
Despite his appearance and personality, Milton has shown himself to have some intelligence, as he was able to accurately define what a Tontine is to the other members of the Flying Hellfish Unit, causing Private Burns to congratulate him.