Even Islamic Scholars agree that this verse from the Christian book of prophesy "Revelation" is about the Mahdi. They however, disagree about what it says about him. Who or what is the Mahdi?
Once upon a time, Imam's were counted as a chain from Mohmmed. Mohammed would be the first Caliph and Imam.. and so it continued. There was a split in the Umma (Islamic world) over succession and the role of Caliph and Imam split. The Shiites are those who followed who they considered to be the legitimate Imam and the Sunni followed the other.. hence the two great houses of Islam - both of whom consider the other to be heretics.
The Twelfth Imam, or the Imam Mahdi, is often called the Last Imam. He, according to Muslim tradition, disappeared down a well with the prophesy to return when the world was drenched in blood, and lead Islam to a war of conquest against the world. Under the Mahdi, there will be two choices, convert to his religion or die.
The Islamic world has been waiting for hundreds of years for the Mahdi's return.. mostly Shiites because they're obsessed with his return. Sunni don't pay as much attention to the prophesy. Within Iran there is a cult called the Twelvers who are fixated on preparing the world for the coming Mahdi. Amadinajad (pronounced "I'm in a Jihad") is a Twelver. The nuclear program, everything, is bent towards bringing about the comming of the Mahdi - he's even prayed for it at the podium of the UN General Assembly.
According to Muslims, the Mahdi will bring "Peace and Justice." Its always best to define your terms. Peace and Justice, as defined by Muslims, is when the world is at peace because they've subjegated it and justice when the entire world is subject to Sharia. This is called Taquilla - holy lying. They say "peace and justice" because they know westerners think of peace and justice in Judeo-Christian terms and so it sounds all sweet and fine, when instead it is patently evil.
I'll save you the long-winded analysis of prophetic scriptures and give you a summary to show the Mahdi is, indeed, what Christianity calls the Anti-Christ.
Christian prophesy fortells the coming world leader who will rise to power and, in the end, force everyone to convert to his religion and worship him. He will have an assistant called the "False Prophet" who's job it is to enforce the faith, cutting the heads off those who will not submit to him. This completes what is called the Satanic Trinity - Satan's imitation of God's triune nature with Satan himself, of course, cast in the role of God.
Islam tells of the coming Mahdi. He will wage a religious war against the world to subject it to Islam and eventually worship of him. He will have an assistant called Isa (which Muslims will tell you is the Jesus of the Bible which is more 'holy lying' to deceive you). Isa's job will be to enforce the faith, cutting the heads off those who refuse to convert to Islam and worship the Mahdi. So, they also have a trinity - Allah, the Mahdi, and Isa.
A comparative study of Islamic prophesy quickly reveals that their prophesy is the same story, except told from the enemy camp.
The Mahdi and the AntiChrist are one in the same.
