Remy Chandler - Series by Thomas Sniegoski
Boston P.I. Remy Chandler has many talents. He can will himself invisible, he can speak and understand any foreign language (including the language of animals), and if he listens carefully, he can hear thoughts.
Unusual, to say the least - for an ordinary man. But Remy is no ordinary man - he's an angel. Generations ago, he chose to renounce heaven and live on Earth. He's found a place among us ordinary humans; friendship, a job he's good at - and love.