Lilia Valeris is a pivotal character in Solar Flare, serving as the adoptive sister of the protagonist, Caelum. She is a bright and compassionate young woman with a strong sense of justice. Lilia is in her late teens, with an optimistic outlook that often contrasts with the darker themes of the story. She has a deep bond with Caelum, providing emotional support and motivation for him as he navigates his identity and the challenges posed by General Zareth.