Summary
Diane Thurston is the granddaughter of Axel and the older sister of Renton. Alongside Axel, she played a pivotal role in raising Renton following the death of their father, Adroc. Several years prior to the main events, Diane departed from her family home, and for reasons initially left unexplained, her relatives have had no contact with her since. Although she appears in family photographs and as a silhouette during the series' opening sequence, her face remains hidden for the first thirty-five episodes; in flashbacks and photos, her visage is consistently obscured. The narration in the early episodes is framed as letters written by Renton to his sister. Diane’s intense obsession with her father’s research strained her relationship with Holland, causing Talho significant anxiety whenever Holland’s past with her is mentioned. While the specific terms of their breakup are not fully detailed, it is deeply connected to Diane’s drive to gain a deeper understanding of Adroc’s work. At some point, Diane found herself in the command center of the Scub Coral. There, within an artificially constructed library, she and a small group of individuals read to uncover the truth they seek. The vast knowledge they pursue would require nearly a lifetime to acquire, and those who remain do so of their own free will. Although Diane promised Renton they would stay together, the command center was destroyed, forcing Renton to leave to save Eureka and the children. It is implied that the command center may return and that both Adroc and Diane are alive, continuing their reading.
