Rayburn Wallack was a civil engineer who worked in the Department of City Planning during the mid- to late-70s. He was by all accounts a deeply unpleasant man: racist, homophobic, anti-Semitic, he felt that the nation as a whole had been going downhill since the censure of Joseph McCarthy. He killed himself in 1981 amidst workplace rumors that he was a homosexual.
Wallack is the only known ghost to have survived the Deluge event of 1983. According to his own version of events, Wallack survived by holing up in a concrete bunker located in the City's subway tunnels (which he'd had built during hiw work in City Planning), lined with the special, incorporeal black metal that is solid to ghosts.
Wallack was destroyed at the outbreak of the Second Deluge, by a reaper that managed to breah the bunker's defenses.