The Burden and Last Fae King

Serena Weir was born into one of the most powerful magical families, yet because she can only use the lowest-ranked F-class mental magic and has long struggled with a weak, overweight body, she has become the laughingstock of Crownspire Academy. After suffering a humiliating defeat in a public trial, she discovers that her longtime boyfriend, Cassian, has been betraying her with her half-sister, Lyla.