Kate Beckett

Katherine "Kate" Houghton Beckett is a detective of the New York City Police Department at the 12th Precinct of the Homicide division and a former Federal government agent. Beckett is now the wife of Richard Castle on Castle and also a crossover on How to Get Away With Murder.

Richard Castle
Richard Castle is Kate Beckett's partner at the 12th precinct in the New York City Police Department. They work on their cases together along with Alexis, Esposito, Ryan, Lanie, and Johnson.

Annalise Keating
Kate and her husband Richard strongly dislikes Annalise Keating due to her actions in Philadelphia as a law professor and a defense attorney.

Martha Rodgers
Martha Rodgers is Kate's mother-in-law in marriage of Richard Castle. They know that Ophelia Harkness is Martha's old friend when they know about Ophelia's daughter Annalise.