Eugene Victor Tooms
- "Mytharc" episodes were recognized as the "mythology" of the series canon; these episodes comprised the central storyline, which developed from one season to the next, concerning extraterrestrial life on Earth and a long-term conspiracy to hide the extraterrestrial presence and deal with its implications.
- Monster of the Week (MOTW or MoW) came to denote the remainder of the X Files episodes. Episodes of this type, comprising the majority of the series's episodes, dealt with a wide range of paranormal phenomena, including cryptids and mutants; science fiction technologies; horror monsters; and satiric/comedic elements. MOTW were usually standalone episodes, but some of these episodes had indirect ties to the X-Files mythology. A number of "monster of the week" characters became notable and were later referenced by other episodes.
This article is thus a list of characters in the Monster of the Week episodes of the X Files.
For characters that were not monsters of the week, see also: List of The X-Files characters.