Yassa was a young black teenage boy, although if still alive he would be an adult by now (since a year passes in the comic strip with each year in the real world). He lived in a small settlement called Bubbletown in the radioactive Cursed Earth desert many miles west of Mega-City One. He owned a dog (unimaginatively named simply "Dog") with abnormally high intelligence, which apparently could understand English, although lacking the ability to speak.