Gray is the son of Alice and Vincent, born from a near-death human child. While he keeps his original name, Samuel, he does respond to the given name Gray. Vincent cast his son out of the Feta Valley at a young age, claiming that he was not pure of heart and should leave until he was pure once more. In reality, Vincent was jealous of the attention Alice was giving their son and wanted him gone. After a while on his own, he met a young human girl named Maria. Maria was a violent and vengeful child who wanted revenge on her own people, but Gray refused to help her participate in this violence and attempted to help change her line of thinking. Eventually, Maria attempted to take her own life, and in order to save her, Gray used his magic to absorb her soul into his own being. Maria's violent tendencies immediately changed Gray, and he too became a violent individual. He was able to regain his own control after a while, though, and after seeing the consequences of what he had done, he vowed to dedicate his life to healing people. He now resides in Sector 7 as its dedicated medic.

Gray is very doting over Johnson and tries to teach him to be a kind and nurturing soul. He is very calm and collected, seeming at peace with the walk of life he has lived. Gray does, however, worry about his companions as a mother hen would her chicks, and this causes a lot of people to see him as soft. He keeps his past a secret from everyone except Zero, and fully intends to take that secret to the grave otherwise.