Robert Langdon is a renowned authority on religious symbols. He has just finished writing a book and is in Paris to give a lecture. His area of expertise draws him into the mystery surrounding the murder in the Louvre Museum. His knowledge and persistence will eventually lead to solving not only the case but also ancient secrets surrounding the Grail.
Sophie Neveu is the granddaughter of Jacques Saunière, who taught her to solve intricate puzzles. She becomes a professional cryptologist—an expert at solving encrypted messages—and takes part in the murder investigation with Langdon.
Sir Leigh Teabing
Sir Leigh Teabing lives outside Paris and uses his enormous wealth to delve into the secrets of the Holy Grail. He is a renowned—if amateur—expert on the subject. He has dedicated his life to finding the Grail, no matter the cost. He is also the Teacher.
Silas is the "muscle" used by the Teacher to force Priory members to reveal what they know about the location of the Grail. Silas's mentor in Opus Dei is Bishop Aringarosa. Silas frequently mortifies his flesh to purify his soul. He follows the orders of the Teacher to do whatever is necessary, including committing murder, to extract information leading to the Grail.