D-Reaper

The D-Reaper, also known as the "True Enemy", is a digital lifeform which appears as the central antagonist in Digimon Tamers. It is referred to as "Matador" (Por: Killer) in Brazilian Digimon Tamers materials.

Unlike most inhabitants of the Digital World in Tamers, it is not a Digimon; while Digimon descend from the virtual wildlife system created by the "Monster Makers", the D-Reaper was allegedly created in the late 1970s by the United States Department of Defense, as an antiviral program for the "Creeper" virus. It is possible it is only a descendant of this program, though, which was then known as the "Reaper", and other theories place its origin with the security program used by the United States Department of National Security in the 1980s for their "ECHELON" project.

The D-Reaper's only purpose is to purge the Digital World once the number of lifeforms within it surpasses a certain number, and it pursues this goal with deadly efficiency.