Blue is a dark blue coloured half breed, being a wolfdog.
At the start of the series, Blue is shown as Quent's pet and aide in hunting wolves, believing, like her master, that wolves were to blame for the destruction of her home and family in Kyrios. She lives her life as a pet dog, unaware of her heritage and helps Quent hunt down every last wolf. Upon meeting Cheza her wolf blood is awakened. Unable to continue hunting down her own kind, she joins the pack in search of Paradise. Blue grows especially close to Hige, promising that she will follow him whatever happens, even if Paradise wouldn't accept her because she is a "half-breed" .Like Toboe, Blue is extremely fond and attached to Humans, having lived with one her whole life. Blue is killed by Darcia protecting Hige and Cheza. She is not seen after earth's regeneration. It is said that Blue may have been reborn in the new world as the kitten Toboe found on the street. However, this is uncertain.
At the start of the series, she seemed to only wanted to protect Quent and complete Quent's goals. Blue was extremely devoted and obedient to Quent and followed his commands without hesistation, even it if meant her own demise. She was even fairly laid-back as she often slept alot. She broke free of following Quent's orders once her inner-wolf had awakened when she had contact with Cheza. We learn that Blue (like Toboe) maintains an affection and a capability of bonding with humans, since she had once lived with a loving family. Like her wolf-dog-self, she is a fairly calm, level-headed individual. Though she seems laid-back she will become fiercely protective and angered if anyone endangers anyone close to her.