The Undertaker Unit, more commonly referred to as the Trashsweepers, was a special forces unit operated by Umbrella. The "Trashsweepers" were tasked with the removal of any evidence of Umbrella's Bio Organic Weaponry. The majority of the soldiers were ironically bio-weapons themselves, so-called "Cleaners". Their commanding officers however, are humans.
In 1998, these units were deployed on Sheena Island, under the command of a human commander to eliminate all B.O.W.s and any possible witness to the incident. The island was eventually destroyed, it is unknown if any of the Cleaners or the commander himself made it out of the island.