"Knightfall Vader" refers to the version of Anakin Skywalker that stormed the Jedi Temple and killed all of the Jedi during the events of "Operation: Knightfall" in the Star Wars universe. This version of Anakin is often considered to be one of the most powerful and dangerous characters in the Star Wars universe. However, it is important to note that "Knightfall Vader" is not a separate character from Darth Vader, but rather a specific version of him.