In the early 1940s, a defunct mineshaft was is bought out by the medicinal corporation █████████. Scrap amounts of iron are found in a stockpile on-site, and shipped out by the company before construction began on a.
By 1980, construction of a storage warehouse was completed to store various supplies used by the company. Built directly atop the mineshaft's entrance, the space at the deepest section of the mineshaft was used by a small group of scientists as a safe space for potentially volatile or otherwise dangerous hybrid species to be held. The only method to get in or out of this section of the building was through an elevator spanning 400 meters deep, which could be manually shut down in case of emergency.
It was found by the scientists that certain materials used for hybridization were molecularly unstable, and required a crystalline 'core' to hold the body together. Among many other fusion results - including a set produced from various pigments of ink - photolytic organisms began to consistently spring up. In an effort to understand why this was happening, four pantherine volunteers were allowed to directly interact with one of the species. Immediately, the Shadow Walker shuffled towards the volunteers and enveloped each one. Each subject was given a protective outfit in order to keep them safe while the actions of the Shadow Walker were studied.
This procedure did not go as planned, however. The suits were unable to protect their wearers, and rather the Tangible Shadow began to solidify, almost visually as melanistic discoloration. The subjects were unable to communicate, and their physique was heavily altered, leading them to be put into cells to be studied along with the other test results. This new species, the Dark Sneps, had not only a combination of the source creatures' anatomy, but also entirely unique features not found on either.