Famlies

While the ability to see ghosts is not a genetic trait, it is not uncommon for generations of families to be chosen to attend a secret academy. The parents raise their kids to understand and believe that such things exist, and many of them naturally fall into the right way of thinking that is required for this special training. Even if the child is not chosen for training, they will grow up in this environment with the knowledge that these things exist. Even without formal training, the child may still gain the ability to see ghosts (or have the ability to a lesser extent and only be able to sense them) simply because of the informal training of their parents and/or siblings. But these people will never have a partner and they will never be able to manifest a mask.