The Antichrist (sometimes known as the King Of Terror) is a figure described in the Book of Revelation in the Christian Bible. He is the archenemy of Christianity and is considered to be the final opponent that mankind shall face before their eventual liberation by Jesus Christ - depictions of the Antichrist vary widely depending on the source and are often a product of politic unrest as it was (and remains) a popular tool of propaganda to infere that your enemy is in some way the Antichrist and thus a figure that must be defeated for the good of all humanity. Therefore he may be considered secondary antagonist in Christianity, the first being The Devil.
Although traditionally seen as a single being their are some people who believe that the Antichrist is actually a being that returns several times throughout human history - this is especially prominent in works by Notradamus: historical-figures who have been considered Antichrists include Napoleon, Hitler and other tyrants as well as traditional enemies of the Christian church such as the Roman Empire (prior to its conversion to Christianity).
The Antichrist is also a popular figure in fiction, undoubtably the most famous of all Antichrists in fiction is Damien Thorn - the antagonist of Omen and its sequels: the idea of the Antichrist as a real figure continues to both terrify and fascinate many people around the world though some people have begun to question whether or not the Antichrist is a threat that awaits humanity, a threat that has already passed or even a metaphor rather than a literal being.
Role Of The Antichrist
The role of the Antichrist, whether it be the singular figure or the ageless figure depicted by Notradamus, remains the same: it is his job to tempt mankind and lead nations to war, to cause sin and corruption to rise and basically create Hell on Earth - taken to its logical conclusion the Antichrist is doing the exact opposite of what Jesus was doing when he was alive: this is a common theme in Christianity in which the Devil and his followers (of which the Antichrist is amongst the most powerful) reverse the traditional roles of religion so as to mock God and his followers.
The Antichrist also takes the place of Jesus in the Unholy Trinity - which consists of Satan, The Antichrist and the False Prophet, a direct opposite of the traditional Holy Trinity - which consists of God, Jesus and the Holy Spirit.