Grampa Simpson is the father of Homer Simpson and is the patriarch of the Simpson family. He is a war veteran and served in World War II with attachments to the navy and air force. For a time he served as the dirty wrestler Glamorous Godfrey, but quite due to being hated for his dirty fighting. Grampa Simpson resides in Springfield Retirement Castle.
Grampa Simpson was made by Matt Groening and appeared in the Simpson episode World War III in a picture and Grandpa and the Kids was his first speaking role.
Abraham 'Abe' Simpson is Homer Simpson's elderly father who lives in an old folks home. He was born in the early 20th Century, and therefore lived through both world wars. He claims to have participated in both wars, although he did have to lie about his age to get into the first.
He moved to America as a young boy, but cannot remember where from. He joined the Army and made a pact with the Hellfish. The last remaining Hellfish (who was alive) would get the hellfish bananza, full of paintings worth millions. Grampa and Mr. Burns were the only two left, and Burns tried to kill Grampa, but failed. When they got the paintings, they were taken by the police and given to the descendant of their rightful owner.
In other universes, he has had superhuman strength and been a member of Oldblood.
On one occasion, he became very rich when he inherited the fortune of an elder lady he had been dating. He held auditions for people who wanted the money. However, he ended donating the money to the care home.