The Ban, also referred as the Settlers, were inhabitants of Erinn, before Irinid banished them and put a curse on them for unknown reasons. The curse made it impossible to live on Erinn. So they created Pincara, a world created through magic and sacrifices, and fled there. To continue Pincara's existence, the Ban created a cloning facility, created with the sacrifice of their leader: Bith.
At one point in the future, the Ban found a crack between the spaces and managed to return to Erinn, only to find that their people were forgotten by Erinn.