Stars serve as a motif of Self-Determination Versus Destiny, playing on a long literary and cultural tradition: Since ancient times, people have associated the stars with fate and sought to predict the future by observing celestial bodies. Thais has an especially close and complicated relationship with the stars because she possesses the power of stellar manipulation. For most of her life, she suppresses this ability because she sees it as a threat to her loved ones and a reminder of the cruelty of her biological father, Olinthar, the Aesymar of Light: “Light gathered around my fingers. […] But even as I reveled in it, the familiar disgust crept in—this gift, this curse, was his” (20). As the story continues, Thais uses her power in ways that both literally and figuratively rewrite the stars. Her abilities grow stronger when she gives in to her desire for Xül, even though their relationship defies the disparate fates that seem chosen for them as a Blessed Mortal and a god. For example, she first summons the cosmic energy required to form a crown of stars after their first kiss.

The authors purposefully keep the motif ambiguous to reflect the unresolved tension between self-determination and destiny. Just as Thais struggles to determine if her choices resist fate or play into its hands, she questions whether her growing mastery over the stars means she’s “finding [her] true self or losing it entirely” (412). A key example of this ambiguity occurs during the climax. Thais kills Olinthar with a sword made of starlight, and his dying words taunt that he lives on in “every star [she] summon[s]” (696). Although Thais’s power grows exponentially over the course of the book, she remains uncertain whether her ability to manipulate the stars represents her agency or her inability to escape her divinely appointed destiny.