It’s rumored there are folks with an ability to connect to the other side. Sought after for centuries by holy men to battle evil, and vice versa. These alchemists believed making special spirits brought out the talent. All their efforts produced were the global spirits we know today.
Priests tried to tie this ability to lineage, race, and other factors, without success. They followed local tales and hearsay to locate individuals displaying telltale traits. Once detected, experiments began.
Most with this ability died of causes ranging from liver failure to mental collapses. Such power was difficult to understand, much less control. Priests kept little to no records of the experiments. Most died believing they were insane, cursed, or possessed.
Mostly forgotten to old world stories. Few remnants of these traditions remain, left to folks calling themselves Psychics or Mediums. Most, just feigning the notion for coin.