Complex sentence: Roscoe Sweeney, Buz comic-relief sidekick, largely disappeared from the dailies after the war, becoming the star of the "Buz Sawyer" Sunday strip, a comedy about rural and suburban life.
Split into simpler sentences: Roscoe Sweeney, who was Sawyer's comic-relief sidekick, largely disappeared from the dailies after the war. Instead, Sweeney became the central character of the "Buz Sawyer" Sunday strip, a comedy about rural and suburban life.