She is part of the mercenary group run by Sei and lives in the group’s hi-tech trailer. She is skilled in combat, firearms usage, and explosive usage. She uses a pair of Desert Eagles to hunt down her targets and her aim has no equal. She has been seen with a rocket launcher from time to time as well. She pilots a mecha named Jango which she can ask for anytime and anywhere from the rest of the crew. She is known to others as “The Angel from Hell.”
She enjoys hunting down bad guys and she likes watching horror movies in her spare time on her own small personal TV set. Her hobby is watching horror movies.Before Jo became a member of Sei's mercenary group, she was rescued by Meg in New York City. She couldn't remember who she was when Meg and orphans found her. The two of them lived together and struggled to survive (as seen in the OVA and first volume of the manga series, both of these focusing on Jo and Meg's pasts).
The reason Jo fights is for Meg. (she says in one of the episode.) There may be a possibility that Jo has romantic feelings for Meg, and Meg for Jo.
Trivia: Interestingly enough, Jo has been appears as flat-chested and rather masculine, whereas the other two Genocide Angles, Lava and Maria, have been shown to be buxom, with a distinct hour-glass figure.