Conversation so far:
what are the signs of imam mahdi coming
The five certain signs of the next Imam are the appearance of Sufyani and Yamani, a sky cry, the murder of an innocent, and the earth swallowing people in Beyda.
what do the signs of imam mahdi coming lead to
The signs of the reappearance of Muhammad al-Mahdi are the collection of events that will occur before the coming back of Muhammad al-Mahdi.

Question: can you tell me about the first sign
Self-contained rewrite: can you tell me about the first sign of imam mahdi coming