[نسايم]

One of the common beliefs among all nations and religions is believing in a divine savior who is the cause of vast blessings and charity for human being. Of course, such savior differs from one nation to another; and it would be discussed in the article: Mahdi (PBUH) in religions.
Believing in a savior is in human's nature that causes hope giving and inspiring. Shia insists explicitly on existence of a savior, Mahdi (PBUH), but the difference is that in Ithna'ashari Shia (1), believing in Mahdi (PBUH) is one of the principles of the school. Prayers to Allah (SWT) and acceptance of worships would be accomplished only by believing in this important base.
In this article Shiite's opinion on definite believing in a savior will be emphasized.
We will declare Mahdi's (PBUH) characteristics from Shiite's point of view, his occultation and his basic role in the world. Also we will explain the era of his reappearance and the golden period of his governorship briefly.
Shiites believe in this heavenly Promised (Mahdi (PBUH)) firmly and has fully talked about him. Below, the aspects of this belief are declared:

Who is the Savior according to Shiite beliefs?
Shiites believe that the Savior (Mahdi (PBUH)) is the ninth descent of Imam Hussain (PBUH), the third Imam of Shiites. Imam Hussain (PBUH) is the son of Imam Ali (PBUH) and Lady Fatimah (PBUH) the Prophet Muhammad's (PBUH&HP) daughter. Mahdi (PBUH) is son of Imam Hassan Askari (PBUH) (the eleventh Imam of Shiites). According to reliable narratives from the Prophet of Islam (PBUH&HP), Mahdi (PBUH) is his namesake. He was born in the city of Samerah in Iraq in year 255 AH (Lunar Calendar). He is one of the people who live much longer than other in history. Shiites believes that he is alive but away from people's eyes. Mahdi's (PBUH) occultation (not absence) is the will of Allah (SWT), however, this occultation has protected his life.
Mahdi (PBUH) is the twelfth Imam of Ithna'ashari Shiites and their greatest leader in the world at present and Shiite's flag is in his hands. His location is not known exactly and Shiites believe that he lives among people.
He is the most pious, just, learned and truthful of all the people. Shia considers him as an infallible (which means he is away from any sin and fault). He is the true interpreter of Holy Quran and the performer of right commandments of Islam. He is the most similar person to Prophet Muhammad (PBUH&HP). Allah (SWT) gives His blessing to the world through Mahdi (PBUH).
He has occulted for an unknown period, but benefits mankind like the sun behind the clouds. He is the kindest of all people and whatever Shiite has is indeed from him. There are many arguments about his occultation, which we will describe in an article titled "Occultation". There would berelief (Faraj)after this occultation by the will of Allah (SWT) which is known as "Reappearance" era.
At first, he will rise from Mecca and will organize a worldwide revolution to spread justice. He will destroy all the wicked and will propagate honesty and theism. He will govern the entire world several years and in the golden era of his appearance, people will experience a divine government, which was desired by all of previous prophets and Imams. In this era, Jesus Christ will come from sky to the earth to help Mahdi (PBUH). The number of his leading companions are 313 (same as the number of soldiers in the first battle of Islam) who are the outstanding people in the history. In fact most of them do not belong to that time but they will gain their lives once again by the command of Allah (SWT) to help Mahdi (PBUH). Further, he will punish the enemies of previous Imams. More details about this era will be discussed in the article: "Reappearance Era".
And finally, after years of his governorship, he will be martyred by the most vicious of all people and that is the time when all people will die and will be raised by Allah's (SWT) will in the day of resurrection for the final judgment.

Footnote:
1- The Shiites who believes in twelve Imams.