Kougyoku is a small young girl with pink eyes and long, dark pink hair, which is pinned up with her golden Metal Vessel. She usually wears a long, elaborate dress signifying her royalty. She carries herself demurely and often hides her face behind her sleeves when embarrassed.
Kougyoku’s greatest charm is her wealth of facial expressions that convey the various changes in her heart. She tends to act childishly, but there are times when Kougyoku, as the stubborn imperial princess, wears a cold mask in order to overwhelm her opponents at a scenes of diplomacy. Even though she puts up such a willful front, she is actually a very lonely person and wants friends. She doesn't want to follow all of the Kou Empire's orders but is too scared to disobey.
She has always wanted to have friends and close companions, but within her family, she has felt ostracized because of her parentage and has not even had the courage to get to know Hakuei or Hakuryuu, the more approachable of her relatives. Instead, she occupied herself with becoming skilled at kemari by herself, playing make-believe by herself, doing a fashion show by herself, etc.
Kougyoku, who was anxious to have a place for herself due to having a complicated lineage, discovers the meaning to her own existence as a soldier. She fights, willingly risking her life for her important people. She holds a pride greater than anyone else. It is as though it is a way for her to confirm her personal sense of existence.
Kougyoku is the youngest daughter of the First Emperor's younger brother, Koutoku Ren. She has a history like Alibaba Saluja: she wasn't born into royalty like her siblings, because she is the daughter of an unknown, lowly courtesan. She calls herself as a "lowborn".
After the death of the Emperor and his heirs in a fire, Kougyoku's father became the Second Emperor, making her the eight Imperial Princess.
Even in the Imperial Palace, since she had no parents or other relatives, she was forgotten by everyone and felt out of place. However, when she was about nine years old, Koubun Ka was assigned to be her assistant. With his persuasion, he was able to make the princess try harder to do her duties, since from that moment on she was the eighth princess and no longer the youngest daughter of the younger brother of the Emperor.
At that time, Judar and her brother Kouen were the only ones to acknowledge her as a King Vessel and gave her the position of a warrior.
She captured the 45th Dungeon and obtained her Djinn, Vinea, with the help of her assistant, Koubun Ka.