Armilus (Hebrew: ארמילוס) (also spelled Armilos and Armilius) is an anti-messiah figure in medieval Jewish eschatology, comparable to medieval interpretations of the Christian Antichrist and Islamic Dajjal, who will conquer Jerusalem and persecute the Jews until his final defeat at the hands of God or the true Messiah. His inevitable destruction symbolizes the ultimate victory of good over evil in the Messianic age.
The Sefer Zerubbabel is probably from the 7th century. Armilus is thought to be a cryptogram for Heraclius and it is thought that the events described in the Sefer Zerubbabel coincide with the Jewish revolt against Heraclius.
The 11th Century Midrash Vayosha, which describes Armilus, was first published at Constantinople in 1519.
According to the Jewish Encyclopedia, Armilus is "a king who will arise at the end of time against the Messiah, and will be conquered by him after having brought much distress upon Israel." He is spoken of in the Midrash Vayosha, Sefer Zerubbabel and other texts. He is an adversary similar to Gog and Magog. In the Sefer Zerubbabel he takes the place of Magog and defeats the Messiah ben Joseph.
The origin of this figure, said to be the offspring of Satan and a virgin, or Satan and a statue (or "stone"), is regarded as questionable by the Jewish Encyclopedia, due to the variation and clear relation (if not parody) to Christian doctrine, legend, and scripture.