The Ostrich Gang was a group of delinquent schoolgirls that would frequently get into trouble with the law. Their gang is never named in the original manga, but in the notes of a story in Neo Devilman they are dubbed the Ostrich Gang.
They are seen late one night waiting for the late teen girl Miko Kawashima to cross their path, when she does they start to harras her and demand that she help them rob a home, she says no and flees from them, they attempt to follow but prove to be to slow compared to Miko. Later the next day two of them catch up to Miko who was going to school, saying that one of them had been caught and they had only just got away, they again pester Miko to rejoin them but she insults them and refuses, this pisses them off and they hold her up against a wall and try to strip off her clothing to humiliate her, however they are repulsed when they see the demon Tollg attached to her body, now enraged she sprays the girls in Tollg's acid causeing them to melt in full view of everyone.
They are seen in the last story of the first volume, As Miko is reflecting on what had happend to them and begs for some kind of forgivness over what she has done.