Though part of human culture for many centuries prior, the existence of Ghosts was not conclusively proven until 1886, when famed Occultist and Spiritualist leader Charles Cornelius Ward was able to produce a "physical" sample - the world's first Ectoplasm. This discovery led to a boom in popularity for the Spiritualist movement, which swept across the United States and Europe as interest in the world of Spirits became part of the public zeitgeist. As increased study of the newly discovered phenomenon continued, the production of Ectoplasm became cheaper and more widespread. It wasn't long before the first "Ghost-Eater" was born - a human being with the ability to utilize injested Ectoplasm to accomplish wild supernatural effects.
The increased interaction between the Spirit World and Earth began to weaken barriers which had kept the two worlds apart, and creatures of Spirit would occasionally begin to cross over, manifesting as monstrous Ectoplasmic forms, and wreaking havoc in their confusion and frustration. Humanity addressed this problem the way they knew best - not by ceasing to explore their new discovery, but by weaponizing the abilities of the Ghost-Eaters, putting them to work against wandering Ghosts, as well as utilizing them in more human-focused conflicts, be those military or against rogue Ghost-Eaters involved with criminal elements.
