I believe this dream occurred because I spent the evening in the presence of Shaykh Muhammad Al Yaqoubi.
I heard Sayyiduna Mahdi’s adhaan from my house, I was lying on my bed at the time, I did not see Sayyiduna Mahdi in the dream. When I heard the adhaan I closed my eyes reading Tasmiyyah three times followed by Allahu Akbar, I remember seeing Shaykh Hisham and Shaykh Muhammad Al Yaqoubi in my dream however on adhaan they vanished. When I opened my eyes I was not in my house, the world was desolate and destruction everywhere, I walked for a long time, whereby I ended at Masjid un Nabawi (saw) – all that hit my eyes was the shining green dome which remained intact and on seeing this I burst into tears and I fell to the floor crying. The dream ended.
Wa Alaykum as Salaam
Their role is to lead to al-Mahdi hence their vanishing when adhan announces him. Everything perishes except connection to Allah which is ta`zim of His Prophet upon him and his family blessings and peace.
Hajj Gibril Haddad