The Walking Ghost started life as Gregori Tataryn. He was born with the potential to gain superhuman powers, but it took exposure to massive amounts of radiation to activate his abilities. After the accident that killed his fellow firefighters and gave him his powers, Gregori came to America and became New York crimelord. His ability to change the density of himself and anything he touches makes him dangerous and hard to capture.
Powers & Abilities
The Walking Ghost can selectively alter the density of whatever he's touching, including himself. He can raise density to make himself indestructible and incredibly strong, or lower it to become untouchable. By imparting these changes to other items, he can make harmless objects into devastating weapons. He has put intangible objects into people and then made them solid again and used keys as a weapon by giving them the mass of a truck before throwing them at an enemy. His only weakness seems to be that he still requires oxygen even in his altered states.