The belief in the Imam Mahdi is a core concept within Shia Islam. According to Shia Islamic eschatology, the Imam Mahdi is a descendant of the Prophet Muhammad who will appear before the Day of Judgement to usher in a period of justice and peace. While the exact timing of his arrival is unknown, many believe he is already alive and in hiding, waiting for the right moment to reveal himself.
It's important to note that this belief is a matter of faith and interpretation within Shia Islam. There are diverse perspectives and interpretations regarding the Imam Mahdi's existence, his current whereabouts, and the events surrounding his appearance. Some believe he is currently alive and hidden, while others believe he has not yet been born.
Ultimately, the question of whether the Imam Mahdi is on Earth is a matter of individual belief and interpretation.
