Yes, according to the Twelver Shia belief described in the provided reference, the Mahdi is considered to be alive, though hidden from humanity.
Based on the doctrine specific to the Twelver Shia, the Mahdi was born but subsequently entered a state of disappearance known as the Occultation.
- He is identified as Muhammad, the son of the eleventh imam, Hasan al-Askari.
- According to this belief, he would remain hidden from humanity during the Occultation.
- He is expected to reappear in the future to establish justice in the world.
Therefore, within this specific Islamic tradition, the belief is that the Mahdi is currently alive but is in a hidden state, awaiting his destined reappearance.