Princess Kagura is an ambitious, as she desires to obtain the Secret Treasure of Mars and become the rightful Queen of Mars. She is also very ruthless and heartless, as she attempted to murder Itall Sonann's entire family in the past, and Yoko in the present.
Thirteen years prior to the events of GUNNM Mars Chronicle, she and Itall Sonann's father met at the Merli Jota Ruins to uncover the Goldstock, one of the two keys to finding the Secret Treasure of Mars. At this time, Princess Kagura possessed the Dornburg Family copy of the book Vom Kriege, the other key to Secret Treasure of Mars.
Immediately after obtaining the Goldstock, Princess Kagura attempted to bury the entire Sonann family alive using explosives. Itall and his father managed to survive the blast, but Itall's sister was gravely injured. Though Itall originally loved her, her actions resulted in the death of Itall's family members and his contraction of the Maske Tumor disease. This caused Itall's love for Princess Kagura to turn to deep hatred, and for him to plot a 10-year revenge.
During the events of GUNNM Mars Chronicle, Princess Kagura became afflicted with severe Maske Tumor disease, leaving her bedridden and grotesquely disfigured. Her status as the Lord of Cydonia grants her the rights to Cydonia's Ethnarch, the Odeon Bach. It is revealed that Yoko originated as one of her maske tumors, which she had been experimenting on extracting and attaching to robotic bodies.
Princess Kagura is bitter enemies with Itall Sonann. Due to certain events, Itall believes that Princess Kagura is responsible for the deaths of his loved ones and his contraction of the Maske Tumor disease. For these reasons, his greatest desire is to bring misery and ruin to Princess Kagura and the region of Cydonia.
Despite being Princess Kagura's uncle, Maruki Baumburg despises her because he wishes to obtain Lordship over Cydonia and access to the Odeon Bach.
Yoko appears physically identical to Princess Kagura, albeit much younger. Yoko has some connection to Princess Kagura, as Yoko has some claim to the Lordship of Cydonia. Princess Kagura does not appear to like Yoko, as she attempted to viciously grab Yoko by the hair. It is also suggested that Princess Kagura attempted to send assassins to kill Yoko.
- It is speculated that Princess Kagura is affiliated with Dasein.
- It is revealed that Yoko was originally a Maske Tumor extracted from Princess Kagura, making them genetic clones. This would explain why Duke Maruki comments that Yoko is not a normal human, though she is still the most valid successor to the Dornburg Lordship of Cydonia.
- It is suggested that Princess Kagura's grandfather (likely, the original Lord Dornburg) was one of Alt Neun.
- Kagura (かぐら) is a Japanese given name, while Dornburg is a German surname. Because it is unlikely that Princess Kagura is married, her name suggests that she is of mixed Japanese and German descent.