Robert E. O. Speedwagon first appears as an Ogre Street thug boss attacking Jonathan, but soon realized the young man's worthiness and dedication, becoming his good friend. He helped uncover Dio's plot to poison George Joestar, and from that point onward he remained by Jonathan's side, helping in whatever way he could to defeat Dio. By the 1930's he is the head of the Speedwagon Foundation, a giant oil company, which assists the Joestar family a great deal in the Series 2-6. In 1952 he dies of a heart attack at age 89. Speedwagon's first three initials are R.E.O; REO Speedwagon is the name of an American rock band of the 70's and 80's. Speedwagon was absent in the 2007 animated movie version of the Phantom Blood story arc.

(Source: Wikipedia)