Madison Hunter

Madison Arabella Watson (née Hunter), also known by her pseudonym Madison A. Hunter, nicknamed affectionately Maddie, by Sherlock and John, is the series main protagonist and is portrayed by Jennifer Morrison. She is the best friend and (second) wife of John Watson, the sister of James and Elizabeth Hunter), the daughter of the late Kevin and Arabella Hunter and mother of Hunter Watson

Biography
Madison is born in Britain to a British father named Kevin and an American mother, Arabella Hunter. However, Madison and her siblings grow up without remembering who their mother is. She and John grow up side by side as siblings and best friends. As she grows up, she begins growing distant and estranged to her eldest sister, Elizabeth ("A Study in Pink", "Hound of the Baskervilles).

Maddie later learned at St. Bart's, along with John and Mike Stamford ("A Study in Pink")

She helped John when they were fighting in the War in Afghanistan. However, when they were out on the field, Madison almost got shot by an enemy soldier, but Watson took the bullet for Hunter, with her only coming out with a broken leg. However, Madison was sent back to England with John and sharing a flat at the retirement home for war veterans before they go and live at Baker Street with Sherlock Holmes.She continuously has nightmares, much to John and Sherlock's horrors.

Sometime after Mary dies, Madison and John have a brief relationship together, unknowingly conceiving a child together. Eventually, Madison gets a pregnancy test and is horrified to learn that she is pregnant with John's child. ("The Six Thatchers", "The Lying Detective", "The Final Problem")

One day, Sherlock goes to the Watson apartment to seek to help both Madison and John. However, Maddie looks at him coldly and says that John would rather have anyone but Sherlock comfort him in the time of grief. Maddie after several sickness days, realizes she is pregnant. Unknown to her and John, Sherlock was given a tape by the late Mary Morstan, asking Sherlock to save her friend and her husband

John Watson
John and Madison have been best friends for a very long time, practically since birth.

Parents
Madison was real close with her father. According to Sherlock, Madison does not know who her mother is and neither does her siblings (however, Sherlock said that only James knows who their mother is.

Siblings
Maddie is close with ehr brother James. However, she is distant towards her sister, Elizabeth after a falling out between both friends. However, thanks to Sherlock, Madison grows close with Elizabeth again.

Trivia

 * n the novels, Madison marries John after the death of his first wife, Mary Morstan. However, in the series, John and her remain neutral after Mary's death with Madison and John potentially becoming love interests
 * She was one of two Mary's maids of honors in John and Mary's wedding towards each other.