Life will become difficult towards the end. Challenges will come. Disasters will come. Injustice will spread across the world.
When we are heading in that direction, the Prophet (SAW) gave us the glad tidings of a righteous ruler who will come. He will fill the Earth with justice and peace. He will be from the lineage of Prophet Muhammad (PBUH).
The age of the Mahdi is the age of intense struggle. In the last campaign when the two sides meet and the Muslims see how many men are there, a third will run away. Their repentance will not be accepted. This is also the time we will be told the Dajjal will be with us.