Terrain first appeared in public as a vigilante fighting alongside the superhuman Thunder, and (according to Max Dalton's first autobiography Giants) was an intelligent, eloquent man. For reasons that remain unclear, after four years Terrain underwent a dramatic mental change to become a rampaging, almost unspeaking villain.

In later years his public appearances were few, but always memorable. It was believed that he had the ability to completely level an entire city, or to raise islands from the ocean. Because of this tremendous power, Terrain garnered an extremely loyal following, especially among certain militant environmentalists, many of whom believed that he was an "Earth-God" whose ultimate purpose was to restore the planet's damaged ecosphere.

Costume:
Terrain was never known to wear any specific costume. The photo here is from police archives, taken immediately after his capture by Energy, three months before the first Mystery Day.