Born in Kenya, Jack's family moved to America when she was very young. At the age of 18 she discovered that there really are monsters under your bed and that she could do something about it by manipulating the water in her bedtime glass.
Jack is a bit of a loner. She is mostly introverted, but she isn't shy and she tends to be friends with specific people instead of groups. Her unique half and half ethnicity has alienated her at times but instead of fighting it, Jack accepted the group alienation. She defines herself by the order, by what she does and she is good at it. She doesn't fight with her body often, though she is capable; Jack prefers to use the wealth of ability she has pertaining to the H2O compound.
Jack usually only carries a daypack around. She has several caches of clothing and money all over the world, but prefers to travel light. The daypack contains certain chemicals to combat the monsters, as well as food, new clothes, money, some weapons and a few personal effects.
Soon after Jack discovered her abilities, she was adopted by the Order, a clandestine group of people that fought the monsters. She was trained to use her abilities to fight the monsters and keep them secret. She was the youngest in her generation. Then her generation of the Order began to die. There were deaths at first that were natural, eventually, however, it became clear that more than natural deaths were occurring. Finally, Jack was the only Order member left from her generation.
She encountered the next generation quite by chance and cringed at the duty she knew was hers: the duty to train them.