A Kiss Before the Apocalypse — Thomas E. Sniegoski

Boston PI Remy Chandler has a life any man would envy, with friendship, a job he's good at -- and love. But Remy is no ordinary man. He's an angel who chose to renounce heaven and live on Earth. So he's able to will himself invisible, hear thoughts, and speak and understand any language -- of man or beast. Talents that will become invaluable to him when his angelic past returns to haunt him...

The Angel of Death has gone missing, and Remy's former colleagues have come to him for help. But what at first seems to be about tracing a missing person turns out to involve much more -- a conspiracy that has as its goal the destruction of the human race.

And only Remy Chandler can stop it....