Diane Thurston is Axel's granddaughter and Renton's older sister. She and Axel were the ones who raised Renton after Adroc's death. She left home some years ago, and for initially unexplained reasons her family has not heard from her since. Despite appearing in Axel's family photos and in a silhouette in the series opening, her face isn't shown for the first 35 episodes —under many different circumstances, her face in flashbacks and photographs is always covered. Much of the first few episode's narration are made as if Renton was writing letters to his sister.   Talho is troubled by Holland's past relationship with her, and reacts with anxiety at her mention. Diane was obsessed with her father's research; so much that it affected her relationship with Holland. The terms of their breakup weren't thoroughly explained, but it's linked with her desire to more deeply understand Adroc's work.   At some point, Diane somehow ended up in the command center of the Scub Coral. There, in a library artificially created by the Scub Coral, she and a small group of people read to understand the truth they seek. The vast knowledge they wish to seek would take almost a lifetime and all that remain are under their own volition. Even though Diane told Renton they'll stay together, the Scub Coral command center was blown away and Renton had to leave in order to save Eureka and the kids. It's suggested that the command center will return again and that Adroc and Diane are alive and well, continuing their reading. 

Renton is a teenager trapped working as a mechanic in a backwater town. He dreams of joining up with a daredevil group of pilots known as Gekkostate and following in his father's heroic footsteps.<br>
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When a mysterious beauty named Eureka shows up asking for a tune-up, Renton soon finds himself drawn into a high-flying mecha dogfight that makes him a target of the military. When the dust settles on the spectacular battle, Renton is invited to join Gekkostate, but he soon discovers that even a dream come true has a dark side.<br>
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(Source: Funimation)

Married to voice actor [Shuuichi Ikeda](https://anilist.co/staff/95598/Shuuichi-Ikeda)

Renton Thurston is a young 14-year-old who is tired of his monotonous life. The only thing that makes him happy is when he "lifts", an extreme form of aerial hoverboarding. His feelings of frustration come from his life of toil in his Grandfather's garage and being the son of an enigmatic yet legendary "hero." One day, a large LFO (Light Finding Operation) craft called Nirvash falls from the sky and a beautiful young girl named Eureka emerges and asks for repairs. When a smitten Renton literally falls over himself to help her, the two begin a journey that will change both of their destinies. 