The phrase used by Drummer, "Unbent, unbowed, unbroken" is the same as the Words (or motto) of House Martell from Game of Thrones (2011), albeit in a different order. This is almost certainly not a coincidence; both Daniel Abraham and Ty Franck, the authors who wrote The Expanse novels under the pen name James S.A. Corey, have worked with the Game of Thrones author George R.R. Martin. Franck was Martin's personal assistant, and Abraham had a number of collaborations with Martin.