Carmen Grant is a high-end con man. In the episode, "Wingman" he is seen as the host of a black market auction for objects of interest to various religions he calls an "Evening of Faith." Included among the items up for sale are the "Lost Chains of St. Paul," the teeth of a saint, "holy napkins," and piece of the cross, as well as Lucifer's wings.
It is apparent that his name is not really Carmen Grant. When Lucifer tries to trace him, he found that, "You, Carmen, slightly more difficult to identify, aren't you? No phone, no bank account, home registered under one of your many aliases."
Carmen had obtained the wings by using a tip from Amenadiel about angel wings in a shipping container at Long Beach and hired Renny to steal them in "Favorite Son." Renny killed a guard in the process, and then threw himself off a roof after having seen them for himself, and then was confronted by the owner. After Carmen received the wings however, he underwent a profound change, "A lifelong atheist, you took one peek at the wings and something changed in you. The great white light was revealed and a believer was born, one who couldn't part with real divinity!" He kept the real wings and mounted them in his house, offering a pair of fakes at the auction. Apparently when he was at home, he spent his time simply gazing at the wings. It was how Lucifer found him when he finally tracks him down.
Carmen, Lucifer, and the wings
Lucifer is appalled at the display and told Carmen, "shame on you." Carmen then pleads with Lucifer, saying that he had no idea what he had been really dealing with, that he had expected a sculpture, but that he now could not live with out them and begged Lucifer not to take them away.
Lucifer growled in a restrained fury, "they're mine!" and then forces a confession from Carmen about who had tipped him off about the wings in the first place. Lucifer then took the wings and destroyed them, Carmen's fate was not discussed.