Bartholomew Sholto is the son of Captain Sholto and the twin brother of Thaddeus Sholto. He is the one who sends the jewels to Miss Morstan after finding out about what his father has done to her father.

Captain Morstan is one of the four who found the treasure. The whole investigation is carried out due to this mans disappearance and why his daughter is receiving the jewels.  

Dr Watson is Sherlock Holmes work partner and a good friend. together they carry out investigations and solve the case.

Jonathan Small, also know as Small is the antagonist of the story. He was one of the four men who discovered the cache of jewels. Small was then captured and passed on the secret to Captain Morstan and Major Sholto.  

Lal Chowder is the servant and faithful friend of Major Sholto. He kept the death of Captain Morstan a secret and helped dispose of the body. 

Major Sholto was an officer and friend of Captain Morstan. Major Sholto is the one who witnessed Captain Morstan having a heart attack, but also the man who hides the body and takes the treasure for himself. He lives the rest of his life haunted by extreme guilt and dies when he sees the face of Jonathon small through a window.

Miss Morstan is the one who brings the case to the attention of Holmes and Watson. she has been searching for her father and has received several mysterious pearls. 

Sherlock Holmes is a brilliant detective with an exceptionally keen eye for detail. Holmes is the one who solves the case with his exceptional skills and early use of forensic science to help solve each case.   

Thaddeus Sholto is the son of Major Sholto and the twin brother of Bartholomew Sholto. He is the one who contacts Holmes and is extremely disappointed with his father's actions. 

The Indian is the servant of Thaddeus Sholtos house. We are first introduced to this man in the opening lines of the story as he leads Miss Morstan, Sherlock Holmes and Dr Watson to Thaddeus.