The Disappearing Mercenaries are a group of soldiers that are under command of Samuel Hill. Their name comes from their corpses disappearing after they die for unknown reasons.
The Disappearing Mercenaries were hired by Professor Shadow to protect his house. Joe was confused of why such an army was needed, but their time came when the house was infiltrated by Cellwind who came to retrieve his Super Mario Odyssey Collectors Coin as well as kill Professor Shadow.
The Disappearing Mercenaries appear to not be a very competent force as the Retarded Door Guard let Cellwind into the house when he was promised candy (he was promptly executed by Cellwind). While the mercs use powerful weapons and their numbers are many, they were easily dispatched by Cellwind. Professor Shadow ended up describing his disappointment with them by claiming it was the, "last time he would buy soldiers on the internet."
Samuel Hill seems to be the only truly competent member of the army as he shows incredible skill in combat. His men seem to have a deep amount of respect for him as one of the mercs was brought to tears when Samuel was killed.