Shortly after the release of the fourth Strike novel, Lethal White, J.K. Rowling announced she was already working on the fifth novel in the series.
In January 2020, Rowling revealed on Twitter than she had finished writing the novel, and on 20th February 2020, the title was announced to be Troubled Blood, with a release date set for 29th September 2020. The publication date was later changed to 15th September 2020.
In January 2020, Marilyn Manson posted on Twitter thanking J.K. Rowling for the flowers she had sent him, leaving fans wondering whether his music will be incorporated into the fifth Strike novel, similar to what she did with Blue Oyster Cult in Career of Evil. However, though this might still be the case, the title Troubled Blood seems to have no relation to any of Manson’s songs.
Below is a fan-made cover of Troubled Blood by Potter Cave in the original style of the first three Strike books.