A Mature Ending: Soulstar by C. L. Polk
Everything Miles, Tristan, Grace, and Avia have worked toward comes to a head in Soulstar, the third and final book in C. L. Polk’s thrilling Kingston Cycle trilogy. The witches are free, but the damage has been done, both to Aeland and its people. With the true evil of Queen Constantina’s asylums now revealed, Robin Thorpe steps in to help out—and to rescue her own spouse, Zelind, a nonbinary witch who has been imprisoned for the last two decades. Robin brings Zelind back to Clan Thorpe...
Source: tor.com