All Ibrahimi religions believe in an end times savior. All Ibrahimi religions believe that someone will emerge who will save the world from the morass of oppression and cruelty. In Islam, the name of this savior has been mentioned.
Immense oppression that prevails throughout the world, the unjust domination, the hounding of nations around the globe; excessive bloodshed, the disregard of the most noble and the most beloved of human values, this is the treachery that the global supercilious front presents to mankind day after day. Immense immorality, exploitation and oppression naturally strikes at one who does not have a spring of hope to cling onto with hopelessness. This is how younger generations in western countries are driven to nihilism. The new generation which has not adapted to nor abides by the traditions, when they see the turbulence of the mankind’s living environment, they lose hope; thus they are driven into nihilism.
An era will emerge when the mighty power of justice will eradicate all summits of corruption and oppression. A new era that will enlighten humankind’s outlook with the light of justice; this is what the awaiting era of Imam Mahdi our Savior signifies.
According to Hadiths, the day of the uprising of Imam Mahdi (A.J) is the Day of Ashura. There is a call in the Month of Ramadhan and then the uprising is on the Day of Ashura. Imam Sadiq (A.S) said:
There would be a call for him in the night of 23 but he will be raised on the Day of Ashura in which Imam Hussain (A.S) was killed.
Imam Khomeini in this regard said as follwoing
It is not such that when we wait for reappearance of the Imām of the Time (PBUH), we should sit at home, pray for his reappearance. His reappearance should be hastened through your struggle... To prepare the ground is achieved by bringing Muslims together and get them united. God willing, he will reappear.
Sahifeh-ye-Imam, Vol.18, page 221
When there is a field of struggle, before the reappearance of the promised Savior, Imam Mahdi. It is in the field of struggle, the pure ones will be examined. They will enter the fields of examination and triumphantly rise from them; thus the world will become nearer to the ideal era and the goal of Imam Mahdi (May our souls be sacrificed for him) day by day. This is a great hope; thus the 15th of Sha’ban is a splendid Eid (celebration).
All Islamic denominations refer to this divine person and this great and extraordinary individual as Mahdi. Perhaps, there is no Islamic denomination that does not believe Mahdi (as) will emerge.
He is a descendent of the Holy Prophet (peace be upon him). Islamic denominations have even specified the name and epithet of that Hazrat. The characteristic of Shia ideology is that it completely and clearly introduces this personality.