Kyuo was a former member of the Septia troupe Phantom, a group of trained hunters who tracked down demon-beasts, capturing and taming them for use in society. Her grandfather, Jin Stolla, was the leader of Phantom and considered to be one of the greatest Septias ever. When Phantom decided to go after the legendary demon beast, the King of the Moon, they had no idea what they were up against. The King of the Moon, whose powers of strength and regeneration were unstoppable while under the moonlight, destroyed an entire village. The Phantom unit tried to stop the beast but they were all wiped out just in one night. In the morning, Kyuo found the corpses of her teammates and buried them.
Kyuo returned to Kuruda and tried to hire a group of thugs to help her hunt down the King of the Moon, but they had other things in mind (a young defenseless girl alone in a bar, you get the idea). Luckily, Elle and Gau overheard the conversation from their table, and Gau immediately jumped right in to defend Kyuo. When the thugs found out that the 59th Sevaar was on Kyuo’s side, they immediately ran for the hills. Kyuo paid Elle for the help, which unfortunately went to cover Elle’s debts. Kyuo offered them more money if they were willing to help her, however Elle was hesitant at first because she thought Kyuo wanted her help to capture the demon-beast. It startled everyone, therefore, when Kyuo admitted that she wanted it dead, not captured – a desire counter to the purpose Septias played in society. Upon that, Elle agreed.
During the hunt, Kyuo showed a remarkable talent for setting traps, as well as handling a series of chakram-like rings called chulinks. These rings are an integral part of a Septia’s abilities and duties, serving as focal points to activate and control their traps. In combat chulinks could also be used as weapons; by attaching a cord to it, a chulink could be used as both a throwing weapon as well as in a way similar to a whip.
That night, the King of the Moon appeared and a fierce battle ensued. Elle and Gau’s attacks were devastating, even so far as splitting the demon-beast in half, but as the fight was occurring beneath a full moon, the demon-beast was able to heal even the most debilitating wounds as soon as they occurred, even regenerate severed limbs. It was Kyuo’s efforts in the end that saved them, her traps pinning the demon-beast in place until the sun rose, and the King of the Moon’s powers waned to the point where it could be, and was, killed. With her revenge now complete, Kyuo had nowhere left to go, so Elle invited her to join the group. She has been with them ever since.
During her stay with the group, Kyuo was often emphasized as the weakest member of the group, especially as compared to Elle and Gau’s Shadow Skills and Faury’s Sui Rem talisman magic. It was also revealed that Kyuo possessed horrific scars on both arms from the early days of her training, a result of mishandling her chulinks. Later on, she met Lowengren, a Vaar who specialized in Open Skills, who fell madly in love with her but whose affections she did not seem to notice. Following the Lightning Battle, Kyuo managed to get some quality time alone with Gau, but Gau’s immense progress left Kyuo afraid of being left behind because she was weak.
In practicing to become stronger, Kyuo was able to successfully master the Tomoway, a style of chulink-throwing and opponent-capturing which her late grandfather was famous for being a master of. One night during her practice, she was confronted with a familiar face, one that she was shocked to see. Her grandfather, or so she thought.
It was actually Iba Stolla, the 55th Sevaar and king of Kuruda, and also Jin Stolla’s twin brother. He revealed to her that he was actually her granduncle and that he would use his power to protect her until the day came that she would find a man who would love and protect her.
During G’s attack, Kyuo did not want Gau to get hurt, and so placed herself on the frontline in order to stop G before Gau would have to fight. However, given that her opponent was a Sevaar, as expected Kyuo lost badly and was very nearly killed. When Gau found her, still alive but bloody and near death, he snapped and in a rage attacked G.
Towards the end of the series, Kyuo suspected that Gau was more than a brother to Elle, but it was not until during Solfon’s attack on Kuruda that she confronted Elle. As a result, their quarrel was cut short. At the end of the series, when Elle was exiled along with Gau, she followed them from the shadows, so as to keep an eye on them.