While the two books in the Six of Crows duology were great, a third spinoff book could tell an incredible revenge story. Leigh Bardugo’s Grishaverse is beloved, but some of the most beloved characters in that beloved universe are Kaz Brekker’s Crows, a.k.a. the Dregs. That includes Kaz’s right-hand woman and master spy, Inej Ghafa, a.k.a. The Wraith. Kaz would never have been able to gain control of the Dregs or pull off the impossible heist of Fjerda’s Ice Court palace without Inej. Kaz is the brains and the mastermind, but without Inej’s skills as a spy, he’d never have had the intel needed to become Dirtyhands.

https://screenrant.com/six-of-crows-third-book-better-revenge-story-inej/