Real Name: Simon Williams
Simon Williams was a competitor of Stark International whose company was bought in a hostile takeover by Tony Stark. Stark wanted to save Willians Technology, but Simon thought that Stark was out to ruin him.
Simon approached his brother, the Grim Reaper, for assistance, and the Grim Reaper arranged for Simon to become the test subject in MODOC's ionic energy experiments. During the procedure, the A.I.M. facility was attacked by Thor and the Wasp, and during the conflict Thor's mystic lightning corrupted the ionic feeds. Simon's body became super-charged with unstable ionic energy, transforming him into Wonder Man.
Wonder Man possesses the ability to change and to fly. His strength and durability are comparable to Thor's. Unfortunately for him, his ionic enery form grew increasingly unstable until he dissapated. Later, his ionic form was reassembled and stablized by the Enchantress, so that Wonder Man could serve Baron Zemo in the Masters of Evil.
Simon Williams, pre-experiment
Simon Williams in the ionic chamber at the A.I.M. facility