The Retro Members is a once-famous battle card guild formed with the belief that using battle cards is a good precursor to monster breeding. To that end, many of the people who join it eventually join one of the monster breeding schools (such as BOMBA or Elives) and go on to be famous monster breeders.
The group is led by Master Oswald, and in recent years has seen a drop in membership because of the allure of some of the flashier groups who are just out for monetary gain. Because of this, Oswald has quit playing battle cards altogether and the group's reputation had suffered.