Lawrence is the secondary antagonist in The Princess and the Frog.
He was initially Naveen's servant, but due to his envy for the Prince's respected life, Lawrence eventually turned to the dark side and worked as Doctor Facilier's minion, and by all accounts, it wasn't much more than an excuse for Lawrence to show how much he hated the prince. At one scene he wanted to call it quits, so he told Doctor Facilier to wear the talisman (at first not knowing that Doctor Facilier couldn't use magic on himself).
After some convincing from Doctor Facilier, Lawrence was back into his plan. Unfortunately, while trying to propose to Charlotte (with sucess) he transforms back to his normal self. Later after Doctor Facilier made his deal with his "friends", Naveen eventually gets captured and his blood was used once again.
At the Mardi Gras parade, just as the minister was about to be finished with the wedding, Naveen escapes the box he was put in and gives the amulet (eventually) to Ray. Lawrence was arrested at the end of the movie.